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Fix corner case of checked div/mod on x86 (#10406)

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Fixes #10377
This commit is contained in:
LemonBoy 2019-01-22 07:33:27 +01:00 • committed by Andreas Rumpf
commit 7a3f382517
1 changed files with 29 additions and 15 deletions
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44
lib/system/arithm.nim
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@ -197,26 +197,40 @@ when asmVersion and not defined(gcc) and not defined(llvm_gcc):
proc divInt(a, b: int): int {.compilerProc, asmNoStackFrame.} =
asm """
mov eax, ecx
mov ecx, edx
xor edx, edx
idiv ecx
jno theEnd
call `raiseOverflow`
theEnd:
test edx, edx
jne L_NOT_ZERO
call `raiseDivByZero`
L_NOT_ZERO:
cmp ecx, 0x80000000
jne L_DO_DIV
cmp edx, -1
jne L_DO_DIV
call `raiseOverflow`
L_DO_DIV:
mov eax, ecx
mov ecx, edx
cdq
idiv ecx
ret
"""
proc modInt(a, b: int): int {.compilerProc, asmNoStackFrame.} =
asm """
mov eax, ecx
mov ecx, edx
xor edx, edx
idiv ecx
jno theEnd
call `raiseOverflow`
theEnd:
mov eax, edx
test edx, edx
jne L_NOT_ZERO
call `raiseDivByZero`
L_NOT_ZERO:
cmp ecx, 0x80000000
jne L_DO_DIV
cmp edx, -1
jne L_DO_DIV
call `raiseOverflow`
L_DO_DIV:
mov eax, ecx
mov ecx, edx
cdq
idiv ecx
mov eax, edx
ret
"""