2020-07-23 20:49:17 +02:00
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# Geometry Transformation Engine (GTE)
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[GTE Overview](geometrytransformationenginegte.md#gte-overview)<br/>
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[GTE Registers](geometrytransformationenginegte.md#gte-registers)<br/>
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[GTE Saturation](geometrytransformationenginegte.md#gte-saturation)<br/>
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[GTE Opcode Summary](geometrytransformationenginegte.md#gte-opcode-summary)<br/>
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[GTE Coordinate Calculation Commands](geometrytransformationenginegte.md#gte-coordinate-calculation-commands)<br/>
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[GTE General Purpose Calculation Commands](geometrytransformationenginegte.md#gte-general-purpose-calculation-commands)<br/>
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[GTE Color Calculation Commands](geometrytransformationenginegte.md#gte-color-calculation-commands)<br/>
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[GTE Division Inaccuracy](geometrytransformationenginegte.md#gte-division-inaccuracy)<br/>
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## GTE Overview
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#### GTE Operation
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The GTE doesn't have any memory or I/O ports mapped to the CPU memory bus,
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instead, it's solely accessed via coprocessor opcodes:<br/>
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```
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mov cop0r12,rt ;-enable/disable COP2 (GTE) via COP0 status register
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mov cop2r0-63,rt ;\write parameters to GTE registers
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mov cop2r0-31,[rs+imm] ;/
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mov cop2cmd,imm25 ;-issue GTE command
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mov rt,cop2r0-63 ;\read results from GTE registers
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mov [rs+imm],cop2r0-31 ;/
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jt cop2flg,dest ;-jump never ;\implemented (no exception), but,
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jf cop2flg,dest ;-jump always ;/flag seems to be always "false"
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```
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GTE (memory-?) load and store instructions have a delay of 2 instructions, for
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any GTE commands or operations accessing that register. Any? That's wrong!<br/>
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GTE instructions and functions should not be used in<br/>
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```
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- Delay slots of jumps and branches
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- Event handlers or interrupts (sounds like nonsense?) (need push/pop though)
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```
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If an instruction that reads a GTE register or a GTE command is executed before
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the current GTE command is finished, the CPU will hold until the instruction
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has finished. The number of cycles each GTE instruction takes is shown in the
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command list.<br/>
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#### GTE Command Encoding (COP2 imm25 opcodes)
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```
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31-25 Must be 0100101b for "COP2 imm25" instructions
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20-24 Fake GTE Command Number (00h..1Fh) (ignored by hardware)
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19 sf - Shift Fraction in IR registers (0=No fraction, 1=12bit fraction)
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17-18 MVMVA Multiply Matrix (0=Rotation. 1=Light, 2=Color, 3=Reserved)
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15-16 MVMVA Multiply Vector (0=V0, 1=V1, 2=V2, 3=IR/long)
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13-14 MVMVA Translation Vector (0=TR, 1=BK, 2=FC/Bugged, 3=None)
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11-12 Always zero (ignored by hardware)
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10 lm - Saturate IR1,IR2,IR3 result (0=To -8000h..+7FFFh, 1=To 0..+7FFFh)
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6-9 Always zero (ignored by hardware)
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0-5 Real GTE Command Number (00h..3Fh) (used by hardware)
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```
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The MVMVA bits are used only by the MVMVA opcode (the bits are zero for all
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other opcodes).<br/>
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The "sf" and "lm" bits are usually fixed (either set, or cleared, depending on
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the command) (for MVMVA, the bits are variable) (also, "sf" can be changed for
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some commands like SQR) (although they are usually fixed for most other
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opcodes, changing them might have some effect on some/all opcodes)?<br/>
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#### GTE Data Register Summary (cop2r0-31)
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```
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cop2r0-1 3xS16 VXY0,VZ0 Vector 0 (X,Y,Z)
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cop2r2-3 3xS16 VXY1,VZ1 Vector 1 (X,Y,Z)
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cop2r4-5 3xS16 VXY2,VZ2 Vector 2 (X,Y,Z)
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cop2r6 4xU8 RGBC Color/code value
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cop2r7 1xU16 OTZ Average Z value (for Ordering Table)
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cop2r8 1xS16 IR0 16bit Accumulator (Interpolate)
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cop2r9-11 3xS16 IR1,IR2,IR3 16bit Accumulator (Vector)
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cop2r12-15 6xS16 SXY0,SXY1,SXY2,SXYP Screen XY-coordinate FIFO (3 stages)
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cop2r16-19 4xU16 SZ0,SZ1,SZ2,SZ3 Screen Z-coordinate FIFO (4 stages)
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cop2r20-22 12xU8 RGB0,RGB1,RGB2 Color CRGB-code/color FIFO (3 stages)
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cop2r23 4xU8 (RES1) Prohibited
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cop2r24 1xS32 MAC0 32bit Maths Accumulators (Value)
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cop2r25-27 3xS32 MAC1,MAC2,MAC3 32bit Maths Accumulators (Vector)
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cop2r28-29 1xU15 IRGB,ORGB Convert RGB Color (48bit vs 15bit)
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cop2r30-31 2xS32 LZCS,LZCR Count Leading-Zeroes/Ones (sign bits)
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```
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#### GTE Control Register Summary (cop2r32-63)
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```
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cop2r32-36 9xS16 RT11RT12,..,RT33 Rotation matrix (3x3) ;cnt0-4
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cop2r37-39 3x 32 TRX,TRY,TRZ Translation vector (X,Y,Z) ;cnt5-7
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cop2r40-44 9xS16 L11L12,..,L33 Light source matrix (3x3) ;cnt8-12
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cop2r45-47 3x 32 RBK,GBK,BBK Background color (R,G,B) ;cnt13-15
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cop2r48-52 9xS16 LR1LR2,..,LB3 Light color matrix source (3x3) ;cnt16-20
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cop2r53-55 3x 32 RFC,GFC,BFC Far color (R,G,B) ;cnt21-23
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cop2r56-57 2x 32 OFX,OFY Screen offset (X,Y) ;cnt24-25
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cop2r58 BuggyU16 H Projection plane distance. ;cnt26
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cop2r59 S16 DQA Depth queing parameter A (coeff) ;cnt27
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cop2r60 32 DQB Depth queing parameter B (offset);cnt28
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cop2r61-62 2xS16 ZSF3,ZSF4 Average Z scale factors ;cnt29-30
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cop2r63 U20 FLAG Returns any calculation errors ;cnt31
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```
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## GTE Registers
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Note in some functions format is different from the one that's given here.<br/>
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#### Matrix Registers
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```
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Rotation matrix (RT) Light matrix (LLM) Light Color matrix (LCM)
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cop2r32.lsbs=RT11 cop2r40.lsbs=L11 cop2r48.lsbs=LR1
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cop2r32.msbs=RT12 cop2r40.msbs=L12 cop2r48.msbs=LR2
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cop2r33.lsbs=RT13 cop2r41.lsbs=L13 cop2r49.lsbs=LR3
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cop2r33.msbs=RT21 cop2r41.msbs=L21 cop2r49.msbs=LG1
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cop2r34.lsbs=RT22 cop2r42.lsbs=L22 cop2r50.lsbs=LG2
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cop2r34.msbs=RT23 cop2r42.msbs=L23 cop2r50.msbs=LG3
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cop2r35.lsbs=RT31 cop2r43.lsbs=L31 cop2r51.lsbs=LB1
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cop2r35.msbs=RT32 cop2r43.msbs=L32 cop2r51.msbs=LB2
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cop2r36 =RT33 cop2r44 =L33 cop2r52 =LB3
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```
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Each element is 16bit (1bit sign, 3bit integer, 12bit fraction). Reading the
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last elements (RT33,L33,LB3) returns the 16bit value sign-expanded to 32bit.<br/>
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#### Translation Vector (TR) (Input, R/W?)
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```
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cop2r37 (cnt5) - TRX - Translation vector X (R/W?)
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cop2r38 (cnt6) - TRY - Translation vector Y (R/W?)
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cop2r39 (cnt7) - TRZ - Translation vector Z (R/W?)
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```
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Each element is 32bit (1bit sign, 31bit integer).<br/>
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Used only for MVMVA, RTPS, RTPT commands.<br/>
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#### Background Color (BK) (Input?, R/W?)
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```
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cop2r45 (cnt13) - RBK - Background color red component
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cop2r46 (cnt14) - GBK - Background color green component
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cop2r47 (cnt15) - BBK - Background color blue component
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```
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Each element is 32bit (1bit sign, 19bit integer, 12bit fraction).<br/>
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#### Far Color (FC) (Input?) (R/W?)
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```
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cop2r53 (cnt21) - RFC - Far color red component
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cop2r54 (cnt22) - GFC - Far color green component
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cop2r55 (cnt23) - BFC - Far color blue component
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```
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Each element is 32bit (1bit sign, 27bit integer, 4bit fraction).<br/>
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#### Screen Offset and Distance (Input, R/W?)
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```
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cop2r56 (cnt24) - OFX - Screen offset X
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cop2r57 (cnt25) - OFY - Screen offset Y
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cop2r58 (cnt26) - H - Projection plane distance
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cop2r59 (cnt27) - DQA - Depth queing parameter A.(coeff.)
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cop2r60 (cnt28) - DQB - Depth queing parameter B.(offset.)
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```
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The X and Y values are each 32bit (1bit sign, 15bit integer, 16bit fraction).<br/>
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The H value is 16bit unsigned (0bit sign, 16bit integer, 0bit fraction). BUG:
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When reading the H register, the hardware does accidently \<sign-expand\>
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the \<unsigned\> 16bit value (ie. values +8000h..+FFFFh are returned as
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FFFF8000h..FFFFFFFFh) (this bug applies only to "mov rd,cop2r58" opcodes; the
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actual calculations via RTPS/RTPT opcodes are working okay).<br/>
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The DQA value is only 16bit (1bit sign, 7bit integer, 8bit fraction).<br/>
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The DQB value is 32bit (1bit sign, 7bit integer, 24bit? fraction).<br/>
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Used only for RTPS/RTPT commands.<br/>
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#### Average Z Registers (ZSF3/ZSF4=Input, R/W?) (OTZ=Result, R)
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```
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cop2r61 (cnt29) ZSF3 | 0|ZSF3 1,3,12| Z3 average scale factor (normally 1/3)
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cop2r62 (cnt30) ZSF4 | 0|ZSF4 1,3,12| Z4 average scale factor (normally 1/4)
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cop2r7 OTZ (R) | |OTZ 0,15, 0| Average Z value (for Ordering Table)
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```
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Used only for AVSZ3/AVSZ4 commands.<br/>
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#### Screen XYZ Coordinate FIFOs
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```
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cop2r12 - SXY0 rw|SY0 1,15, 0|SX0 1,15, 0| Screen XY fifo (older)
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cop2r13 - SXY1 rw|SY1 1,15, 0|SX1 1,15, 0| Screen XY fifo (old)
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cop2r14 - SXY2 rw|SY2 1,15, 0|SX2 1,15, 0| Screen XY fifo (new)
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cop2r15 - SXYP rw|SYP 1,15, 0|SXP 1,15, 0| SXY2-mirror with move-on-write
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cop2r16 - SZ0 rw| 0|SZ0 0,16, 0| Screen Z fifo (oldest)
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cop2r17 - SZ1 rw| 0|SZ1 0,16, 0| Screen Z fifo (older)
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cop2r18 - SZ2 rw| 0|SZ2 0,16, 0| Screen Z fifo (old)
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cop2r19 - SZ3 rw| 0|SZ3 0,16, 0| Screen Z fifo (new)
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```
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SX,SY,SZ are used as Output for RTPS/RTPT. Additionally, SX,SY are used as
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Input for NCLIP, and SZ is used as Input for AVSZ3/AVSZ4.<br/>
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The SZn Fifo has 4 stages (required for AVSZ4 command), the SXYn Fifo has only
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3 stages, and a special mirrored register: SXYP is a mirror of SXY2, the
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difference is that writing to SXYP moves SXY2/SXY1 to SXY1/SXY0, whilst writing
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to SXY2 (or any other SXYn or SZn registers) changes only the written register,
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but doesn't move any other Fifo entries.<br/>
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#### 16bit Vectors (R/W)
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```
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Vector 0 (V0) Vector 1 (V1) Vector 2 (V2) Vector 3 (IR)
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cop2r0.lsbs - VX0 cop2r2.lsbs - VX1 cop2r4.lsbs - VX2 cop2r9 - IR1
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cop2r0.msbs - VY0 cop2r2.msbs - VY1 cop2r4.msbs - VY2 cop2r10 - IR2
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cop2r1 - VZ0 cop2r3 - VZ1 cop2r5 - VZ2 cop2r11 - IR3
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```
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All elements are signed 16bit. The IRn and VZn elements occupy a whole 32bit
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register, reading these registers returns the 16bit value sign-expanded to
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32bit. Note: IRn can be also indirectly accessed via IRGB/ORGB registers.<br/>
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#### Color Register and Color FIFO
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```
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cop2r6 - RGBC rw|CODE |B |G |R | Color/code
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cop2r20 - RGB0 rw|CD0 |B0 |G0 |R0 | Characteristic color fifo.
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cop2r21 - RGB1 rw|CD1 |B1 |G1 |R1 |
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cop2r22 - RGB2 rw|CD2 |B2 |G2 |R2 |
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cop2r23 - (RES1) | | Prohibited
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```
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RES1 seems to be unused... looks like an unused Fifo stage... RES1 is
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read/write-able... unlike SXYP (for SXYn Fifo) it does not mirror to RGB2, nor
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does it have a move-on-write function...<br/>
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#### Interpolation Factor
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```
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cop2r8 IR0 rw|Sign |IR0 1, 3,12| Intermediate value 0.
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```
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Used as Output for RTPS/RTPT, and as Input for various commands.<br/>
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#### XX...
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```
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cop2r24 MAC0 rw|MAC0 1,31,0 | Sum of products value 0
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```
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#### XX...
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```
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cop2r25 MAC1 rw|MAC1 1,31,0 | Sum of products value 1
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cop2r26 MAC2 rw|MAC2 1,31,0 | Sum of products value 2
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cop2r27 MAC3 rw|MAC3 1,31,0 | Sum of products value 3
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```
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#### cop2r28 - IRGB - Color conversion Input (R/W)
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Expands 5:5:5 bit RGB (range 0..1Fh) to 16:16:16 bit RGB (range 0000h..0F80h).<br/>
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```
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0-4 Red (0..1Fh) (R/W) ;multiplied by 80h, and written to IR1
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5-9 Green (0..1Fh) (R/W) ;multiplied by 80h, and written to IR2
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10-14 Blue (0..1Fh) (R/W) ;multiplied by 80h, and written to IR3
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15-31 Not used (always zero) (Read only)
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```
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After writing to IRGB, the result can be read from IR3 after TWO nop's, and
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from IR1,IR2 after THREE nop's (for uncached code, ONE nop would work). When
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using IR1,IR2,IR3 as parameters for GTE commands, similar timing restrictions
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might apply... depending on when the specific commands use the parameters?<br/>
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#### cop2r29 - ORGB - Color conversion Output (R)
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Collapses 16:16:16 bit RGB (range 0000h..0F80h) to 5:5:5 bit RGB (range
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0..1Fh). Negative values (8000h..FFFFh/80h) are saturated to 00h, large
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positive values (1000h..7FFFh/80h) are saturated to 1Fh, there are no overflow
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or saturation flags set in cop2r63 though.<br/>
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```
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0-4 Red (0..1Fh) (R) ;IR1 divided by 80h, saturated to +00h..+1Fh
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5-9 Green (0..1Fh) (R) ;IR2 divided by 80h, saturated to +00h..+1Fh
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|
10-14 Blue (0..1Fh) (R) ;IR3 divided by 80h, saturated to +00h..+1Fh
|
|
|
|
|
15-31 Not used (always zero) (Read only)
|
|
|
|
|
```
|
|
|
|
|
Any changes to IR1,IR2,IR3 are reflected to this register (and, actually also
|
|
|
|
|
to IRGB) (ie. ORGB is simply a read-only mirror of IRGB).<br/>
|
|
|
|
|
|
|
|
|
|
#### cop2r30 - LZCS - Count Leading Bits Source data (R/W)
|
|
|
|
|
#### cop2r31 - LZCR - Count Leading Bits Result (R)
|
|
|
|
|
Reading LZCR returns the leading 0 count of LZCS if LZCS is positive and the
|
|
|
|
|
leading 1 count of LZCS if LZCS is negative. The results are in range 1..32.<br/>
|
|
|
|
|
|
|
|
|
|
#### cop2r63 (cnt31) - FLAG - Returns any calculation errors.
|
|
|
|
|
See GTE Saturation chapter.<br/>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
## GTE Saturation
|
|
|
|
|
Maths overflows are indicated in FLAG register. In most cases, the result is
|
|
|
|
|
saturated to MIN/MAX values (except MAC0,MAC1,MAC2,MAC3 which aren't
|
|
|
|
|
saturated). For IR1,IR2,IR3 many commands allow to select the MIN value via
|
|
|
|
|
"lm" bit of the GTE opcode (though not all commands, RTPS/RTPT always act as if
|
|
|
|
|
lm=0).<br/>
|
|
|
|
|
|
|
|
|
|
#### cop2r63 (cnt31) - FLAG - Returns any calculation errors.
|
|
|
|
|
```
|
|
|
|
|
31 Error Flag (Bit30..23, and 18..13 ORed together) (Read only)
|
|
|
|
|
30 MAC1 Result larger than 43 bits and positive
|
|
|
|
|
29 MAC2 Result larger than 43 bits and positive
|
|
|
|
|
28 MAC3 Result larger than 43 bits and positive
|
|
|
|
|
27 MAC1 Result larger than 43 bits and negative
|
|
|
|
|
26 MAC2 Result larger than 43 bits and negative
|
|
|
|
|
25 MAC3 Result larger than 43 bits and negative
|
|
|
|
|
24 IR1 saturated to +0000h..+7FFFh (lm=1) or to -8000h..+7FFFh (lm=0)
|
|
|
|
|
23 IR2 saturated to +0000h..+7FFFh (lm=1) or to -8000h..+7FFFh (lm=0)
|
|
|
|
|
22 IR3 saturated to +0000h..+7FFFh (lm=1) or to -8000h..+7FFFh (lm=0)
|
|
|
|
|
21 Color-FIFO-R saturated to +00h..+FFh
|
|
|
|
|
20 Color-FIFO-G saturated to +00h..+FFh
|
|
|
|
|
19 Color-FIFO-B saturated to +00h..+FFh
|
|
|
|
|
18 SZ3 or OTZ saturated to +0000h..+FFFFh
|
|
|
|
|
17 Divide overflow. RTPS/RTPT division result saturated to max=1FFFFh
|
|
|
|
|
16 MAC0 Result larger than 31 bits and positive
|
|
|
|
|
15 MAC0 Result larger than 31 bits and negative
|
|
|
|
|
14 SX2 saturated to -0400h..+03FFh
|
|
|
|
|
13 SY2 saturated to -0400h..+03FFh
|
|
|
|
|
12 IR0 saturated to +0000h..+1000h
|
|
|
|
|
0-11 Not used (always zero) (Read only)
|
|
|
|
|
```
|
|
|
|
|
Bit30-12 are read/write-able, ie. they can be set/reset by software, however,
|
|
|
|
|
that's normally not required - all bits are automatically reset at the begin of
|
|
|
|
|
a new GTE command.<br/>
|
|
|
|
|
Bit31 is apparently intended for RTPS/RTPT commands, since it triggers only on
|
|
|
|
|
flags that are affected by these two commands, but even for that commands it's
|
|
|
|
|
totally useless since one could as well check if FLAG is nonzero.<br/>
|
|
|
|
|
Note: Writing 32bit values to 16bit GTE registers by software does not trigger
|
|
|
|
|
any overflow/saturation flags (and does not do any saturation), eg. writing
|
|
|
|
|
12008900h (positive 32bit) to a signed 16bit register sets that register to
|
|
|
|
|
FFFF8900h (negative 16bit).<br/>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
## GTE Opcode Summary
|
|
|
|
|
#### GTE Command Summary (sorted by Real Opcode bits) (bit0-5)
|
|
|
|
|
```
|
|
|
|
|
Opc Name Clk Expl.
|
|
|
|
|
00h - N/A (modifies similar registers than RTPS...)
|
|
|
|
|
01h RTPS 15 Perspective Transformation single
|
|
|
|
|
0xh - N/A
|
|
|
|
|
06h NCLIP 8 Normal clipping
|
|
|
|
|
0xh - N/A
|
|
|
|
|
0Ch OP(sf) 6 Outer product of 2 vectors
|
|
|
|
|
0xh - N/A
|
|
|
|
|
10h DPCS 8 Depth Cueing single
|
|
|
|
|
11h INTPL 8 Interpolation of a vector and far color vector
|
|
|
|
|
12h MVMVA 8 Multiply vector by matrix and add vector (see below)
|
|
|
|
|
13h NCDS 19 Normal color depth cue single vector
|
|
|
|
|
14h CDP 13 Color Depth Que
|
|
|
|
|
15h - N/A
|
|
|
|
|
16h NCDT 44 Normal color depth cue triple vectors
|
|
|
|
|
1xh - N/A
|
|
|
|
|
1Bh NCCS 17 Normal Color Color single vector
|
|
|
|
|
1Ch CC 11 Color Color
|
|
|
|
|
1Dh - N/A
|
|
|
|
|
1Eh NCS 14 Normal color single
|
|
|
|
|
1Fh - N/A
|
|
|
|
|
20h NCT 30 Normal color triple
|
|
|
|
|
2xh - N/A
|
|
|
|
|
28h SQR(sf)5 Square of vector IR
|
|
|
|
|
29h DCPL 8 Depth Cue Color light
|
|
|
|
|
2Ah DPCT 17 Depth Cueing triple (should be fake=08h, but isn't)
|
|
|
|
|
2xh - N/A
|
|
|
|
|
2Dh AVSZ3 5 Average of three Z values
|
|
|
|
|
2Eh AVSZ4 6 Average of four Z values
|
|
|
|
|
2Fh - N/A
|
|
|
|
|
30h RTPT 23 Perspective Transformation triple
|
|
|
|
|
3xh - N/A
|
|
|
|
|
3Dh GPF(sf)5 General purpose interpolation
|
|
|
|
|
3Eh GPL(sf)5 General purpose interpolation with base
|
|
|
|
|
3Fh NCCT 39 Normal Color Color triple vector
|
|
|
|
|
```
|
|
|
|
|
Unknown if/what happens when using the "N/A" opcodes?<br/>
|
|
|
|
|
|
|
|
|
|
#### GTE Command Summary (sorted by Fake Opcode bits) (bit20-24)
|
|
|
|
|
The fake opcode number in bit20-24 has absolutely no effect on the hardware, it
|
|
|
|
|
seems to be solely used to (or not to) confuse developers. Having the opcodes
|
|
|
|
|
sorted by their fake numbers gives a more or less well arranged list:<br/>
|
|
|
|
|
```
|
|
|
|
|
Fake Name Clk Expl.
|
|
|
|
|
00h - N/A
|
|
|
|
|
01h RTPS 15 Perspective Transformation single
|
|
|
|
|
02h RTPT 23 Perspective Transformation triple
|
|
|
|
|
03h - N/A
|
|
|
|
|
04h MVMVA 8 Multiply vector by matrix and add vector (see below)
|
|
|
|
|
05h - N/A
|
|
|
|
|
06h DCPL 8 Depth Cue Color light
|
|
|
|
|
07h DPCS 8 Depth Cueing single
|
|
|
|
|
08h DPCT 17 Depth Cueing triple (should be fake=08h, but isn't)
|
|
|
|
|
09h INTPL 8 Interpolation of a vector and far color vector
|
|
|
|
|
0Ah SQR(sf)5 Square of vector IR
|
|
|
|
|
0Bh - N/A
|
|
|
|
|
0Ch NCS 14 Normal color single
|
|
|
|
|
0Dh NCT 30 Normal color triple
|
|
|
|
|
0Eh NCDS 19 Normal color depth cue single vector
|
|
|
|
|
0Fh NCDT 44 Normal color depth cue triple vectors
|
|
|
|
|
10h NCCS 17 Normal Color Color single vector
|
|
|
|
|
11h NCCT 39 Normal Color Color triple vector
|
|
|
|
|
12h CDP 13 Color Depth Que
|
|
|
|
|
13h CC 11 Color Color
|
|
|
|
|
14h NCLIP 8 Normal clipping
|
|
|
|
|
15h AVSZ3 5 Average of three Z values
|
|
|
|
|
16h AVSZ4 6 Average of four Z values
|
|
|
|
|
17h OP(sf) 6 Outer product of 2 vectors
|
|
|
|
|
18h - N/A
|
|
|
|
|
19h GPF(sf)5 General purpose interpolation
|
|
|
|
|
1Ah GPL(sf)5 General purpose interpolation with base
|
|
|
|
|
1Bh - N/A
|
|
|
|
|
1Ch - N/A
|
|
|
|
|
1Dh - N/A
|
|
|
|
|
1Eh - N/A
|
|
|
|
|
1Fh - N/A
|
|
|
|
|
```
|
|
|
|
|
For the sort-effect, DCPT should use fake=08h, but Sony seems to have
|
|
|
|
|
accidently numbered it fake=0Fh in their devkit (giving it the same fake number
|
|
|
|
|
as for NCDT). Also, "Wipeout 2097" accidently uses 0140006h (fake=01h and
|
|
|
|
|
distorted bit18) instead of 1400006h (fake=14h) for NCLIP.<br/>
|
|
|
|
|
|
|
|
|
|
#### Additional Functions
|
|
|
|
|
The LZCS/LZCR registers offer a Count-Leading-Zeroes/Leading-Ones function.<br/>
|
|
|
|
|
The IRGB/ORGB registers allow to convert between 48bit and 15bit RGB colors.<br/>
|
|
|
|
|
These registers work without needing to send any COP2 commands. However, unlike
|
|
|
|
|
for commands (which do automatically halt the CPU when needed), one must insert
|
|
|
|
|
dummy opcodes between writing and reading the registers.<br/>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
## GTE Coordinate Calculation Commands
|
|
|
|
|
#### COP2 0180001h - 15 Cycles - RTPS - Perspective Transformation (single)
|
|
|
|
|
#### COP2 0280030h - 23 Cycles - RTPT - Perspective Transformation (triple)
|
|
|
|
|
RTPS performs final Rotate, translate and perspective transformation on vertex
|
|
|
|
|
V0. Before writing to the FIFOs, the older entries are moved one stage down.
|
|
|
|
|
RTPT is same as RTPS, but repeats for V1 and V2. The "sf" bit should be usually
|
|
|
|
|
set.<br/>
|
|
|
|
|
```
|
|
|
|
|
IR1 = MAC1 = (TRX*1000h + RT11*VX0 + RT12*VY0 + RT13*VZ0) SAR (sf*12)
|
|
|
|
|
IR2 = MAC2 = (TRY*1000h + RT21*VX0 + RT22*VY0 + RT23*VZ0) SAR (sf*12)
|
|
|
|
|
IR3 = MAC3 = (TRZ*1000h + RT31*VX0 + RT32*VY0 + RT33*VZ0) SAR (sf*12)
|
|
|
|
|
SZ3 = MAC3 SAR ((1-sf)*12) ;ScreenZ FIFO 0..+FFFFh
|
|
|
|
|
MAC0=(((H*20000h/SZ3)+1)/2)*IR1+OFX, SX2=MAC0/10000h ;ScrX FIFO -400h..+3FFh
|
|
|
|
|
MAC0=(((H*20000h/SZ3)+1)/2)*IR2+OFY, SY2=MAC0/10000h ;ScrY FIFO -400h..+3FFh
|
|
|
|
|
MAC0=(((H*20000h/SZ3)+1)/2)*DQA+DQB, IR0=MAC0/1000h ;Depth cueing 0..+1000h
|
|
|
|
|
```
|
2020-07-23 22:41:06 +02:00
|
|
|
If the result of the "(((H\*20000h/SZ3)+1)/2)" division is greater than 1FFFFh,
|
2020-07-23 20:49:17 +02:00
|
|
|
then the division result is saturated to +1FFFFh, and the divide overflow bit
|
|
|
|
|
in the FLAG register gets set; that happens if the vertex is exceeding the
|
|
|
|
|
"near clip plane", ie. if it is very close to the camera (SZ3\<=H/2), exactly
|
|
|
|
|
at the camara position (SZ3=0), or behind the camera (negative Z coordinates
|
|
|
|
|
are saturated to SZ3=0). For details on the division, see:<br/>
|
|
|
|
|
[GTE Division Inaccuracy](geometrytransformationenginegte.md#gte-division-inaccuracy)<br/>
|
|
|
|
|
For "far plane clipping", one can use the SZ3 saturation flag (MaxZ=FFFFh), or
|
|
|
|
|
the IR3 saturation flag (MaxZ=7FFFh) (eg. used by Wipeout 2097), or one can
|
|
|
|
|
compare the SZ3 value with any desired MaxZ value by software.<br/>
|
|
|
|
|
Note: The command does saturate IR1,IR2,IR3 to -8000h..+7FFFh (regardless of lm
|
|
|
|
|
bit). When using RTP with sf=0, then the IR3 saturation flag (FLAG.22) gets set
|
|
|
|
|
\<only\> if "MAC3 SAR 12" exceeds -8000h..+7FFFh (although IR3 is saturated
|
|
|
|
|
when "MAC3" exceeds -8000h..+7FFFh).<br/>
|
|
|
|
|
|
|
|
|
|
#### COP2 1400006h - 8 Cycles - NCLIP - Normal clipping
|
|
|
|
|
```
|
|
|
|
|
MAC0 = SX0*SY1 + SX1*SY2 + SX2*SY0 - SX0*SY2 - SX1*SY0 - SX2*SY1
|
|
|
|
|
```
|
|
|
|
|
The sign of the result indicates whether the polygon coordinates are arranged
|
|
|
|
|
clockwise or anticlockwise (ie. whether the front side or backside is visible).
|
|
|
|
|
If the result is zero, then it's neither one (ie. the vertices are all arranged
|
|
|
|
|
in a straight line). Note: The GPU probably renders straight lines as invisble
|
|
|
|
|
0 pixel width lines?<br/>
|
|
|
|
|
|
|
|
|
|
#### COP2 158002Dh - 5 Cycles - AVSZ3 - Average of three Z values (for Triangles)
|
|
|
|
|
#### COP2 168002Eh - 6 Cycles - AVSZ4 - Average of four Z values (for Quads)
|
|
|
|
|
```
|
|
|
|
|
MAC0 = ZSF3*(SZ1+SZ2+SZ3) ;for AVSZ3
|
|
|
|
|
MAC0 = ZSF4*(SZ0+SZ1+SZ2+SZ3) ;for AVSZ4
|
|
|
|
|
OTZ = MAC0/1000h ;for both (saturated to 0..FFFFh)
|
|
|
|
|
```
|
|
|
|
|
Adds three or four Z values together and multplies them by a fixed point value.
|
|
|
|
|
The result can be used as index in the GPU's Ordering Table (OT).<br/>
|
|
|
|
|
[GPU Depth Ordering](graphicsprocessingunitgpu.md#gpu-depth-ordering)<br/>
|
|
|
|
|
The scaling factors would be usually ZSF3=N/30h and ZSF4=N/40h, where "N" is
|
|
|
|
|
the number of entries in the OT (max 10000h). SZn and OTZ are unsigned 16bit
|
|
|
|
|
values, for whatever reason ZSFn registers are signed 16bit values (negative
|
|
|
|
|
values would allow a negative result in MAC0, but would saturate OTZ to zero).<br/>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
## GTE General Purpose Calculation Commands
|
|
|
|
|
#### COP2 0400012h - 8 Cycles - MVMVA(sf,mx,v,cv,lm)
|
|
|
|
|
Multiply vector by matrix and vector addition.<br/>
|
|
|
|
|
```
|
|
|
|
|
Mx = matrix specified by mx ;RT/LLM/LCM - Rotation, light or color matrix
|
|
|
|
|
Vx = vector specified by v ;V0, V1, V2, or [IR1,IR2,IR3]
|
|
|
|
|
Tx = translation vector specified by cv ;TR or BK or Bugged/FC, or None
|
|
|
|
|
```
|
|
|
|
|
Calculation:<br/>
|
|
|
|
|
```
|
|
|
|
|
MAC1 = (Tx1*1000h + Mx11*Vx1 + Mx12*Vx2 + Mx13*Vx3) SAR (sf*12)
|
|
|
|
|
MAC2 = (Tx2*1000h + Mx21*Vx1 + Mx22*Vx2 + Mx23*Vx3) SAR (sf*12)
|
|
|
|
|
MAC3 = (Tx3*1000h + Mx31*Vx1 + Mx32*Vx2 + Mx33*Vx3) SAR (sf*12)
|
|
|
|
|
[IR1,IR2,IR3] = [MAC1,MAC2,MAC3]
|
|
|
|
|
```
|
|
|
|
|
Multiplies a vector with either the rotation matrix, the light matrix or the
|
|
|
|
|
color matrix and then adds the translation vector or background color vector.<br/>
|
|
|
|
|
The GTE also allows selection of the far color vector (FC), but this vector is
|
|
|
|
|
not added correctly by the hardware: The return values are reduced to the last
|
2020-07-23 22:41:06 +02:00
|
|
|
portion of the formula, ie. MAC1=(Mx13\*Vx3) SAR (sf\*12), and similar for MAC2
|
2020-07-23 20:49:17 +02:00
|
|
|
and MAC3, nethertheless, some bits in the FLAG register seem to be adjusted as
|
|
|
|
|
if the full operation would have been executed. Setting Mx=3 selects a garbage
|
|
|
|
|
matrix (with elements -60h, +60h, IR0, RT13, RT13, RT13, RT22, RT22, RT22).<br/>
|
|
|
|
|
|
2020-07-23 22:41:06 +02:00
|
|
|
#### COP2 0A00428h+sf\*80000h - 5 Cycles - SQR(sf) - Square vector
|
2020-07-23 20:49:17 +02:00
|
|
|
```
|
|
|
|
|
[MAC1,MAC2,MAC3] = [IR1*IR1,IR2*IR2,IR3*IR3] SHR (sf*12)
|
|
|
|
|
[IR1,IR2,IR3] = [MAC1,MAC2,MAC3] ;IR1,IR2,IR3 saturated to max 7FFFh
|
|
|
|
|
```
|
|
|
|
|
Calculates the square of a vector. The result is, of course, always positive,
|
|
|
|
|
so the "lm" flag for negative saturation has no effect.<br/>
|
|
|
|
|
|
2020-07-23 22:41:06 +02:00
|
|
|
#### COP2 170000Ch+sf\*80000h - 6 Cycles - OP(sf,lm) - Outer product of 2 vectors
|
2020-07-23 20:49:17 +02:00
|
|
|
```
|
|
|
|
|
[MAC1,MAC2,MAC3] = [IR3*D2-IR2*D3, IR1*D3-IR3*D1, IR2*D1-IR1*D2] SAR (sf*12)
|
|
|
|
|
[IR1,IR2,IR3] = [MAC1,MAC2,MAC3] ;copy result
|
|
|
|
|
```
|
|
|
|
|
Calculates the outer product of two signed 16bit vectors. Note: D1,D2,D3 are
|
|
|
|
|
meant to be the RT11,RT22,RT33 elements of the RT matrix "misused" as vector.
|
|
|
|
|
lm should be usually zero.<br/>
|
|
|
|
|
|
|
|
|
|
#### LZCS/LZCR registers - ? Cycles - Count-Leading-Zeroes/Leading-Ones
|
|
|
|
|
The LZCS/LZCR registers offer a Count-Leading-Zeroes/Leading-Ones function.<br/>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
## GTE Color Calculation Commands
|
|
|
|
|
#### COP2 0C8041Eh - 14 Cycles - NCS - Normal color (single)
|
|
|
|
|
#### COP2 0D80420h - 30 Cycles - NCT - Normal color (triple)
|
|
|
|
|
#### COP2 108041Bh - 17 Cycles - NCCS - Normal Color Color (single vector)
|
|
|
|
|
#### COP2 118043Fh - 39 Cycles - NCCT - Normal Color Color (triple vector)
|
|
|
|
|
#### COP2 0E80413h - 19 Cycles - NCDS - Normal color depth cue (single vector)
|
|
|
|
|
#### COP2 0F80416h - 44 Cycles - NCDT - Normal color depth cue (triple vectors)
|
|
|
|
|
In: V0=Normal vector (for triple variants repeated with V1 and V2),
|
|
|
|
|
BK=Background color, RGBC=Primary color/code, LLM=Light matrix, LCM=Color
|
|
|
|
|
matrix, IR0=Interpolation value.<br/>
|
|
|
|
|
```
|
|
|
|
|
[IR1,IR2,IR3] = [MAC1,MAC2,MAC3] = (LLM*V0) SAR (sf*12)
|
|
|
|
|
[IR1,IR2,IR3] = [MAC1,MAC2,MAC3] = (BK*1000h + LCM*IR) SAR (sf*12)
|
|
|
|
|
[MAC1,MAC2,MAC3] = [R*IR1,G*IR2,B*IR3] SHL 4 ;<--- for NCDx/NCCx
|
|
|
|
|
[MAC1,MAC2,MAC3] = MAC+(FC-MAC)*IR0 ;<--- for NCDx only
|
|
|
|
|
[MAC1,MAC2,MAC3] = [MAC1,MAC2,MAC3] SAR (sf*12) ;<--- for NCDx/NCCx
|
|
|
|
|
Color FIFO = [MAC1/16,MAC2/16,MAC3/16,CODE], [IR1,IR2,IR3] = [MAC1,MAC2,MAC3]
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
#### COP2 138041Ch - 11 Cycles - CC(lm=1) - Color Color
|
|
|
|
|
#### COP2 1280414h - 13 Cycles - CDP(...) - Color Depth Que
|
|
|
|
|
In: [IR1,IR2,IR3]=Vector, RGBC=Primary color/code, LCM=Color matrix,
|
|
|
|
|
BK=Background color, and, for CDP, IR0=Interpolation value, FC=Far color.<br/>
|
|
|
|
|
```
|
|
|
|
|
[IR1,IR2,IR3] = [MAC1,MAC2,MAC3] = (BK*1000h + LCM*IR) SAR (sf*12)
|
|
|
|
|
[MAC1,MAC2,MAC3] = [R*IR1,G*IR2,B*IR3] SHL 4
|
|
|
|
|
[MAC1,MAC2,MAC3] = MAC+(FC-MAC)*IR0 ;<--- for CDP only
|
|
|
|
|
[MAC1,MAC2,MAC3] = [MAC1,MAC2,MAC3] SAR (sf*12)
|
|
|
|
|
Color FIFO = [MAC1/16,MAC2/16,MAC3/16,CODE], [IR1,IR2,IR3] = [MAC1,MAC2,MAC3]
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
#### COP2 0680029h - 8 Cycles - DCPL - Depth Cue Color light
|
|
|
|
|
#### COP2 0780010h - 8 Cycles - DPCS - Depth Cueing (single)
|
|
|
|
|
#### COP2 0x8002Ah - 17 Cycles - DPCT - Depth Cueing (triple)
|
|
|
|
|
#### COP2 0980011h - 8 Cycles - INTPL - Interpolation of a vector and far color
|
|
|
|
|
In: [IR1,IR2,IR3]=Vector, FC=Far Color, IR0=Interpolation value, CODE=MSB of
|
|
|
|
|
RGBC, and, for DCPL, R,G,B=LSBs of RGBC.<br/>
|
|
|
|
|
```
|
|
|
|
|
[MAC1,MAC2,MAC3] = [R*IR1,G*IR2,B*IR3] SHL 4 ;<--- for DCPL only
|
|
|
|
|
[MAC1,MAC2,MAC3] = [IR1,IR2,IR3] SHL 12 ;<--- for INTPL only
|
|
|
|
|
[MAC1,MAC2,MAC3] = [R,G,B] SHL 16 ;<--- for DPCS/DPCT
|
|
|
|
|
[MAC1,MAC2,MAC3] = MAC+(FC-MAC)*IR0
|
|
|
|
|
[MAC1,MAC2,MAC3] = [MAC1,MAC2,MAC3] SAR (sf*12)
|
|
|
|
|
Color FIFO = [MAC1/16,MAC2/16,MAC3/16,CODE], [IR1,IR2,IR3] = [MAC1,MAC2,MAC3]
|
|
|
|
|
```
|
|
|
|
|
DPCT executes thrice, and reads the R,G,B values from RGB0 (ie. reads from the
|
|
|
|
|
Bottom of the Color FIFO, instead of from the RGBC register) (the CODE value is
|
|
|
|
|
kept read from RGBC as usually), so, after DPCT execution, the RGB0,RGB1,RGB2
|
|
|
|
|
Fifo entries are modified.<br/>
|
|
|
|
|
|
|
|
|
|
#### COP2 190003Dh - 5 Cycles - GPF(sf,lm) - General purpose Interpolation
|
|
|
|
|
#### COP2 1A0003Eh - 5 Cycles - GPL(sf,?) - General Interpolation with base
|
|
|
|
|
```
|
|
|
|
|
[MAC1,MAC2,MAC3] = [0,0,0] ;<--- for GPF only
|
|
|
|
|
[MAC1,MAC2,MAC3] = [MAC1,MAC2,MAC3] SHL (sf*12) ;<--- for GPL only
|
|
|
|
|
[MAC1,MAC2,MAC3] = (([IR1,IR2,IR3] * IR0) + [MAC1,MAC2,MAC3]) SAR (sf*12)
|
|
|
|
|
Color FIFO = [MAC1/16,MAC2/16,MAC3/16,CODE], [IR1,IR2,IR3] = [MAC1,MAC2,MAC3]
|
|
|
|
|
```
|
|
|
|
|
Note: Although the SHL in GPL is theoretically undone by the SAR, 44bit
|
|
|
|
|
overflows can occur internally when sf=1.<br/>
|
|
|
|
|
|
2020-07-23 22:41:06 +02:00
|
|
|
#### Details on "MAC+(FC-MAC)\*IR0"
|
2020-07-23 20:49:17 +02:00
|
|
|
```
|
|
|
|
|
[IR1,IR2,IR3] = (([RFC,GFC,BFC] SHL 12) - [MAC1,MAC2,MAC3]) SAR (sf*12)
|
|
|
|
|
[MAC1,MAC2,MAC3] = (([IR1,IR2,IR3] * IR0) + [MAC1,MAC2,MAC3])
|
|
|
|
|
```
|
|
|
|
|
Note: Above "[IR1,IR2,IR3]=(FC-MAC)" is saturated to -8000h..+7FFFh (ie. as if
|
|
|
|
|
lm=0), anyways, further writes to [IR1,IR2,IR3] (within the same command) are
|
|
|
|
|
saturated as usually (ie. depening on lm setting).<br/>
|
|
|
|
|
|
2020-07-23 22:41:06 +02:00
|
|
|
#### Details on "(LLM\*V0) SAR (sf\*12)" and "(BK\*1000h + LCM\*IR) SAR (sf\*12)"
|
2020-07-23 20:49:17 +02:00
|
|
|
Works like MVMVA command (see there), but with fixed Tx/Vx/Mx parameters, the
|
|
|
|
|
sf/lm bits can be changed and do affect the results (although normally both
|
|
|
|
|
bits should be set for use with color matrices).<br/>
|
|
|
|
|
|
|
|
|
|
#### Notes
|
|
|
|
|
The 8bit RGB values written to the top of Color Fifo are the 32bit MACn values
|
|
|
|
|
divided by 16, and saturated to +00h..+FFh, and of course, the older Fifo
|
|
|
|
|
entries are moved downwards. Note that, at the GPU side, the meaning of the RGB
|
|
|
|
|
values depends on whether or not texture blending is used (for untextured
|
|
|
|
|
polygons FFh is max brightness) (for texture blending FFh is double brightness
|
|
|
|
|
and 80h is normal brightness).<br/>
|
|
|
|
|
The 8bit CODE value is intended to contain a GP0(20h..7Fh) Rendering command,
|
|
|
|
|
allowing to automatically merge the 8bit command number, with the 24bit color
|
|
|
|
|
value.<br/>
|
|
|
|
|
The IRGB/ORGB registers allow to convert between 48bit and 15bit RGB colors.<br/>
|
|
|
|
|
Although the result of the commands in this chapter is written to the Color
|
|
|
|
|
FIFO, some commands like GPF/GPL may be also used for other purposes (eg. to
|
|
|
|
|
scale or scale/translate single vertices).<br/>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
## GTE Division Inaccuracy
|
|
|
|
|
#### GTE Division Inaccuracy (for RTPS/RTPT commands)
|
|
|
|
|
Basically, the GTE division does (attempt to) work as so (using 33bit maths):<br/>
|
|
|
|
|
```
|
|
|
|
|
n = (((H*20000h/SZ3)+1)/2)
|
|
|
|
|
```
|
|
|
|
|
alternatly, below would give (almost) the same result (using 32bit maths):<br/>
|
|
|
|
|
```
|
|
|
|
|
n = ((H*10000h+SZ3/2)/SZ3)
|
|
|
|
|
```
|
|
|
|
|
in both cases, the result is saturated about as so:<br/>
|
|
|
|
|
```
|
|
|
|
|
if n>1FFFFh or division_by_zero then n=1FFFFh, FLAG.Bit17=1, FLAG.Bit31=1
|
|
|
|
|
```
|
|
|
|
|
However, the real GTE hardware is using a fast, but less accurate division
|
|
|
|
|
mechanism (based on Unsigned Newton-Raphson (UNR) algorithm):<br/>
|
|
|
|
|
```
|
|
|
|
|
if (H < SZ3*2) then ;check if overflow
|
|
|
|
|
z = count_leading_zeroes(SZ3) ;z=0..0Fh (for 16bit SZ3)
|
|
|
|
|
n = (H SHL z) ;n=0..7FFF8000h
|
|
|
|
|
d = (SZ3 SHL z) ;d=8000h..FFFFh
|
|
|
|
|
u = unr_table[(d-7FC0h) SHR 7] + 101h ;u=200h..101h
|
|
|
|
|
d = ((2000080h - (d * u)) SHR 8) ;d=10000h..0FF01h
|
|
|
|
|
d = ((0000080h + (d * u)) SHR 8) ;d=20000h..10000h
|
|
|
|
|
n = min(1FFFFh, (((n*d) + 8000h) SHR 16)) ;n=0..1FFFFh
|
|
|
|
|
else n = 1FFFFh, FLAG.Bit17=1, FLAG.Bit31=1 ;n=1FFFFh plus overflow flag
|
|
|
|
|
```
|
2020-07-23 22:41:06 +02:00
|
|
|
the GTE's unr\_table[000h..100h] consists of following values:<br/>
|
2020-07-23 20:49:17 +02:00
|
|
|
```
|
|
|
|
|
FFh,FDh,FBh,F9h,F7h,F5h,F3h,F1h,EFh,EEh,ECh,EAh,E8h,E6h,E4h,E3h ;\
|
|
|
|
|
E1h,DFh,DDh,DCh,DAh,D8h,D6h,D5h,D3h,D1h,D0h,CEh,CDh,CBh,C9h,C8h ; 00h..3Fh
|
|
|
|
|
C6h,C5h,C3h,C1h,C0h,BEh,BDh,BBh,BAh,B8h,B7h,B5h,B4h,B2h,B1h,B0h ;
|
|
|
|
|
AEh,ADh,ABh,AAh,A9h,A7h,A6h,A4h,A3h,A2h,A0h,9Fh,9Eh,9Ch,9Bh,9Ah ;/
|
|
|
|
|
99h,97h,96h,95h,94h,92h,91h,90h,8Fh,8Dh,8Ch,8Bh,8Ah,89h,87h,86h ;\
|
|
|
|
|
85h,84h,83h,82h,81h,7Fh,7Eh,7Dh,7Ch,7Bh,7Ah,79h,78h,77h,75h,74h ; 40h..7Fh
|
|
|
|
|
73h,72h,71h,70h,6Fh,6Eh,6Dh,6Ch,6Bh,6Ah,69h,68h,67h,66h,65h,64h ;
|
|
|
|
|
63h,62h,61h,60h,5Fh,5Eh,5Dh,5Dh,5Ch,5Bh,5Ah,59h,58h,57h,56h,55h ;/
|
|
|
|
|
54h,53h,53h,52h,51h,50h,4Fh,4Eh,4Dh,4Dh,4Ch,4Bh,4Ah,49h,48h,48h ;\
|
|
|
|
|
47h,46h,45h,44h,43h,43h,42h,41h,40h,3Fh,3Fh,3Eh,3Dh,3Ch,3Ch,3Bh ; 80h..BFh
|
|
|
|
|
3Ah,39h,39h,38h,37h,36h,36h,35h,34h,33h,33h,32h,31h,31h,30h,2Fh ;
|
|
|
|
|
2Eh,2Eh,2Dh,2Ch,2Ch,2Bh,2Ah,2Ah,29h,28h,28h,27h,26h,26h,25h,24h ;/
|
|
|
|
|
24h,23h,22h,22h,21h,20h,20h,1Fh,1Eh,1Eh,1Dh,1Dh,1Ch,1Bh,1Bh,1Ah ;\
|
|
|
|
|
19h,19h,18h,18h,17h,16h,16h,15h,15h,14h,14h,13h,12h,12h,11h,11h ; C0h..FFh
|
|
|
|
|
10h,0Fh,0Fh,0Eh,0Eh,0Dh,0Dh,0Ch,0Ch,0Bh,0Ah,0Ah,09h,09h,08h,08h ;
|
|
|
|
|
07h,07h,06h,06h,05h,05h,04h,04h,03h,03h,02h,02h,01h,01h,00h,00h ;/
|
|
|
|
|
00h ;<-- one extra table entry (for "(d-7FC0h)/80h"=100h) ;-100h
|
|
|
|
|
```
|
2020-07-23 22:41:06 +02:00
|
|
|
Above can be generated as "unr\_table[i]=min(0,(40000h/(i+100h)+1)/2-101h)".<br/>
|
2020-07-23 20:49:17 +02:00
|
|
|
Some special cases: NNNNh/0001h uses a big multiplier (d=20000h), in practice,
|
2020-07-23 22:41:06 +02:00
|
|
|
this can occur only for 0000h/0001h and 0001h/0001h (due to the H\<SZ3\*2
|
2020-07-23 20:49:17 +02:00
|
|
|
overflow check).<br/>
|
|
|
|
|
The min(1FFFFh) limit is needed for cases like FE3Fh/7F20h, F015h/780Bh, etc.
|
|
|
|
|
(these do produce UNR result 20000h, and are saturated to 1FFFFh, but without
|
|
|
|
|
setting overflow FLAG bits).<br/>
|
