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kvisc/vm/pc/DECD
2019-07-24 16:52:26 +02:00

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# The OS/K Team licenses this file to you under the MIT license.
# See the LICENSE file in the project root for more information.
Instruction encoding:
Byte 1: Instruction number
Byte 2:
xx0xxxxx
|| └───┘
RL CND
Values for ModRMs:
000xxxxx xxxxx = reg
(for memory accesses, xxxxx = access size)
001xxxxx [reg]
010xxxxx [reg+reg]
011xxxxx [reg+reg+imm16]
100xxxxx [reg+reg+imm32]
101xxxxx [reg+reg*imm8+imm32]
110xxxxx [reg+imm64]
11100001 imm8 (zero extended)
11100010 imm16 (zero extended)
11100100 imm32 (zero extended)
11101000 imm64 (zero extended)
Values for COND:
00000 (none)
00001 .C .B
00010 .O
00011 .Z .E
00100 .S
00101 .P
00110 .BE
00111 .L
01000 .LE
01001 .AXZ
01010 .BXZ
01011 .CXZ
01100 .DXZ
Highest (6th) bit of COND indicates negation