Retro/pcjs
Watch
1
0
Fork
You've already forked pcjs
 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

More FPU work

Browse source
This commit is contained in:
Jeff Parsons 2015-11-16 17:41:55 -08:00
commit d9e280f279
4 changed files with 638 additions and 180 deletions
Download patch file Download diff file Expand all files Collapse all files

46
modules/pcjs/lib/x86ops.js
View file

@ -1097,6 +1097,52 @@ X86.opPUSHBX = function()
/**
* op=0x54 (PUSH SP)
*
* NOTE: Having an accurate implementation of "PUSH SP" for the 8086/8088 isn't just a nice idea, it affects real
* code. Case in point: early Microsoft C floating-point libraries relied on "PUSH SP" behavior to quickly determine
* whether an 8088 (and therefore presumably an 8087) or an 80286 (and presumably an 80287) was being used; eg:
*
* &0910:1E82 D93E1709 FSTCW WORD [0917]
* &0910:1E86 CD3D INT 3D
* &0E4E:06D3 50 PUSH AX
* &0E4E:06D4 B83DA2 MOV AX,A23D
* &0E4E:06D7 EB04 JMP 06DD
* &0E4E:06DD 55 PUSH BP
* &0E4E:06DE 1E PUSH DS
* &0E4E:06DF 56 PUSH SI
* &0E4E:06E0 8BEC MOV BP,SP
* &0E4E:06E2 C57608 LDS SI,[BP+08]
* &0E4E:06E5 4E DEC SI
* &0E4E:06E6 4E DEC SI
* &0E4E:06E7 897608 MOV [BP+08],SI
* &0E4E:06EA 2904 SUB [SI],AX
* &0E4E:06EC 53 PUSH BX
* &0E4E:06ED 33DB XOR BX,BX
* &0E4E:06EF 54 PUSH SP ; beginning of processor check
* &0E4E:06F0 58 POP AX
* &0E4E:06F1 3BC4 CMP AX,SP
* &0E4E:06F3 7528 JNZ 071D ; jump if 8086/8088/80186/80188, no jump if 80286 or later
* &0E4E:06F5 8B4001 MOV AX,[BX+SI+01]
* &0E4E:06F8 25FB30 AND AX,30FB
* &0E4E:06FB 3DD930 CMP AX,30D9
* &0E4E:06FE 7507 JNZ 0707
* &0E4E:0700 8A4002 MOV AL,[BX+SI+02]
* &0E4E:0703 3CF0 CMP AL,F0
* &0E4E:0705 7216 JC 071D
* &0E4E:0707 8B4001 MOV AX,[BX+SI+01]
* &0E4E:070A 25FFFE AND AX,FEFF
* &0E4E:070D 3DDBE2 CMP AX,E2DB
* &0E4E:0710 740B JZ 071D
* &0E4E:0712 8B4001 MOV AX,[BX+SI+01]
* &0E4E:0715 3DDFE0 CMP AX,E0DF
* &0E4E:0718 7403 JZ 071D
* &0E4E:071A C60490 MOV [SI],90
* &0E4E:071D 5B POP BX
* &0E4E:071E 5E POP SI
* &0E4E:071F 1F POP DS
* &0E4E:0720 5D POP BP
* &0E4E:0721 58 POP AX
* &0E4E:0722 CF IRET
*
* @this {X86CPU}
*/
X86.opPUSHSP_8086 = function()