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Document lines with overlapping vertices

This commit is contained in:
wheremyfoodat 2022-08-29 04:16:43 +03:00
parent 9db9fafd62
commit bc58f2b8dc
2 changed files with 5 additions and 4 deletions
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6
docs/cpuspecifications.md
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@ -351,12 +351,12 @@ Note that the instruction following the branch will always be executed.<br/>
bgez rs,dest if rs>=0 then pc=$+4+(-8000h..+7FFFh)*4
bgtz rs,dest if rs>0 then pc=$+4+(-8000h..+7FFFh)*4
blez rs,dest if rs<=0 then pc=$+4+(-8000h..+7FFFh)*4
bltzal rs,dest ra=$+8; if rs<0 then pc=$+4+(..)*4
bgezal rs,dest ra=$+8; if rs>=0 then pc=$+4+(..)*4
bltzal rs,dest if rs<0 then pc=$+4+(..)*4; ra=$+8;
bgezal rs,dest if rs>=0 then pc=$+4+(..)*4; ra=$+8;
```
jr/jalr can be used to jump to an unaligned address, in which case an address error (AdEL) exception will be raised on the next instruction fetch.<br/>
Additionally, bltzal/bgezal will always place the return address in $ra, whether or not the branch is taken<br/>
Additionally, bltzal/bgezal will always place the return address in $ra, whether or not the branch is taken. Additionally, if `rs` is $ra, then the value used for the comparison is $ra's value before linking.<br/>
#### JALR cautions
Caution: The JALR source code syntax varies (IDT79R3041 specs say "jalr rs,rd",

3
docs/graphicsprocessingunitgpu.md
View File

@ -231,8 +231,9 @@ Vertex YYYYXXXX - required, two signed 16 bits values
When polyline mode is active, at least two vertices must be sent to the GPU.
The vertex list is terminated by the bits 12-15 and 28-31 equaling `0x5`, or
`(word & 0xF000F000) == 0x50005000`. The terminator value occurs on the first
word of the vertex (i.e. the color word if it's a gouraud shaded).
word of the vertex (i.e. the color word if it's a gouraud shaded).<br/>
If the 2 vertices in a line overlap, then the GPU will draw a 1x1 rectangle in the location of the 2 vertices using the colour of the first vertex.
#### Note
Lines are displayed up to \<including\> their lower-right coordinates (ie.