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Fixed divide-by-zero and data breakpoint exception dispatching

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This commit is contained in:
Jeff Parsons 2015-10-18 10:57:51 -07:00
commit d1d733e38b
8 changed files with 144 additions and 105 deletions
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51
tests/pc/80386/test386.nasm
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@ -107,6 +107,18 @@ DSEG_PROT16 equ 0x0018
DSEG_PROT32 equ 0x0020
SSEG_PROT32 equ 0x0028
OFF_INTDIVERR equ 0xe000
;
; The "defGate" macro defines an interrupt gate, given a selector (%1) and an offset (%2)
;
%macro defGate 2
dw (%2 & 0xffff)
dw %1
dw ACC_TYPE_GATE386_INT | ACC_PRESENT
dw (%2 >> 16) & 0xffff
%endmacro
;
; The "defDesc" macro defines a descriptor, given a name (%1), base (%2), limit (%3), type (%4), and ext (%5)
;
@ -205,6 +217,12 @@ myGDT: defDesc NULL ; the first descriptor in any descriptor table is always a
defDesc SSEG_PROT32,0x00010000,0x000effff,ACC_TYPE_DATA_WRITABLE,EXT_BIG
myGDTEnd:
addrIDT:dw myIDTEnd - myIDT - 1 ; 16-bit limit of myIDT
dw myIDT, 0x000f ; 32-bit base address of myIDT
myIDT: defGate CSEG_PROT32,OFF_INTDIVERR
myIDTEnd:
initGDT:
%ifdef RAM_GDT
set edi,RAM_GDT
@ -241,6 +259,9 @@ initGDT:
mov eax,edx ; recover the base address of the current CS
add eax,myGDT ; EAX == physical address of myGDT
mov [cs:addrGDT+2],eax ; update the 32-bit base address of myGDT in addrGDT
mov eax,edx ; recover the base address of the current CS again
add eax,myIDT ; EAX == physical address of myIDT
mov [cs:addrIDT+2],eax ; update the 32-bit base address of myIDT in addrIDT
mov ax,cs
%ifdef REAL32
mov [cs:jmpReal+5],ax ; update the segment of the FAR jump that returns us to real-mode
@ -318,6 +339,7 @@ initPT: stosd
goProt:
cli ; make sure interrupts are off now, since we've not initialized the IDT yet
o32 lidt [cs:addrIDT]
o32 lgdt [cs:addrGDT]
mov cr3,esi
mov eax,cr0
@ -748,8 +770,10 @@ SIZE_LONG equ 2
%%beg:
%ifidni %4,none
%2 %3
%else
%elifidni %5,none
%2 %3,%4
%else
%2 %3,%4,%5
%endif
ret
%%end:
@ -758,6 +782,7 @@ SIZE_LONG equ 2
strEAX: db "EAX=",0
strEDX: db "EDX=",0
strPS: db "PS=",0
strDE: db "#DE ",0 ; when this is displayed, it indicates a Divide Error exception
achSize db "BWD"
tableOps:
@ -796,6 +821,13 @@ tableOps:
defOp "IMULA",imul,edx,none,none,TYPE_MULDIV
defOp "IMUL",imul,ax,dx,none,TYPE_MULDIV
defOp "IMUL",imul,eax,edx,none,TYPE_MULDIV
defOp "IMUL8",imul,ax,dx,0x77,TYPE_ARITH1
defOp "IMUL8",imul,ax,dx,-0x77,TYPE_ARITH1
defOp "IMUL8",imul,eax,edx,0x77,TYPE_ARITH1
defOp "IMUL8",imul,eax,edx,-0x77,TYPE_ARITH1
defOp "IMUL16",imul,ax,0x777,none,TYPE_ARITH1
defOp "IMUL32",imul,eax,0x777777,none,TYPE_ARITH1
defOp "IDIVA",idiv,dl,none,none,TYPE_MULDIV
db 0
align 4
@ -858,6 +890,23 @@ typeValues:
error: jmp error
times OFF_INTDIVERR-0x100-($-$$) nop
intDivErr:
push esi
mov esi,strDE
call printStr
pop esi
;
; It's rather annoying that the 80386 treats #DE as a fault rather than a trap, leaving CS:EIP pointing to the
; faulting instruction. So we must "patch" the EIP on the stack to point to a RET; it's easier to use our own RET
; rather than figuring out how long the DIV instruction is.
;
mov dword [esp],intDivRet
iretd
intDivRet:
ret
doneProt:
mov ax,DSEG_PROT16
mov ss,ax

2
tests/pc/inc/x86.inc
View file

@ -17,6 +17,7 @@ PS_MULDIV equ (PS_CF | PS_OF)
CR0_MSW_PE equ 0x0001
CR0_PG equ 0x80000000 ; set if paging enabled
ACC_TYPE_GATE386_INT equ 0x0E00
ACC_TYPE_SEG equ 0x1000
ACC_PRESENT equ 0x8000
ACC_TYPE_CODE equ 0x0800
@ -25,6 +26,7 @@ ACC_TYPE_WRITABLE equ 0x0200
ACC_TYPE_CODE_READABLE equ 0x1a00
ACC_TYPE_DATA_WRITABLE equ 0x1200
EXT_NONE equ 0x0000
EXT_BIG equ 0x0040