此错误已在 RAD Studio 10.2 Tokyo 中修复。该问题可以在这里找到(但必须使用 embarcadero 帐户登录才能看到它)。
这是 John O'Harrow 的 __llmulo 的正确版本(在 MPL 1.1 下获得许可)随 Delphi 10.2 及更高版本一起提供:
// Param 1(edx:eax), Param 2([esp+8]:[esp+4])
// Result is stored in edx:eax
// O-flag set on exit => result is invalid
// O-flag clear on exit => result is valid
procedure __llmulo();
asm
test edx, edx {Param1-Hi = 0?}
jne @@Large {No, More than one multiply may be needed}
cmp edx, [esp+8] {Param2-Hi = 0?}
jne @@Large {No, More than one multiply may be needed}
mul dword ptr [esp+4] {Only one multiply needed, Set Result}
and eax, eax {Clear Overflow Flag}
ret 8
@@Large:
sub esp, 28 {allocate local storage}
mov [esp], ebx {save used registers}
mov [esp+4], esi
mov [esp+8], edi
mov [esp+12], ebp
mov ebx, [esp+32] {Param2-Lo}
mov ecx, [esp+36] {Param2-Hi}
mov esi, edx
mov edi, ecx
sar esi, 31
sar edi, 31
xor eax, esi
xor edx, esi
sub eax, esi
sbb edx, esi {edx:eax (a1:a0) = abs(Param1)}
xor ebx, edi
xor ecx, edi
sub ebx, edi
sbb ecx, edi {ecx:ebx (b1:b0) = abs(Param2)}
xor esi, edi {Sign Flag, 0 if Params have same sign else -1}
mov [esp+16], eax {a0}
mov [esp+20], edx {a1}
mov [esp+24], ecx {b1}
mul ebx {edx:eax (c1:c0) = a0*b0}
xchg ebx, edx {ebx = c1, edx = b0}
mov edi, eax {abs(Result-Lo) = c0}
xor ecx, ecx {Upper 32 bits of 128 bit result}
xor ebp, ebp {Second 32 bits of 128 bit result}
mov eax, [esp+20] {a1}
mul edx {edx:eax (d1:d0) = a1*b0}
add ebx, eax {c1 + d0}
adc ebp, edx {d1 + carry}
adc ecx, 0 {Possible carry into Upper 32 bits}
mov eax, [esp+16] {a0}
mov edx, [esp+24] {b1}
mul edx {edx:eax (e1:e0) = a0*b1}
add ebx, eax {abs(Result-Hi) = c1 + d0 + e0}
adc ebp, edx {d1 + e1 + carry}
adc ecx, 0 {Possible carry into Upper 32 bits}
mov eax, [esp+20] {a1}
mov edx, [esp+24] {b1}
mul edx {edx:eax (f1:f0) = a1*b1}
add ebp, eax {d1 + e1 + f0 + carry}
adc ecx, edx {f1 + carry}
or ecx, ebp {Overflow if ecx <> 0 or ebp <> 0}
jnz @@Overflow
mov edx, ebx {Set abs(Result-Hi)}
mov eax, edi {Set abs(Result-Lo)}
cmp edx, $80000000
jae @@CheckRange {Possible Overflow if edx>=$80000000}
@@SetSign:
xor eax, esi {Correct Sign of Result}
xor edx, esi
sub eax, esi
sbb edx, esi
mov ebx, [esp] {restore used registers}
mov esi, [esp+4]
mov edi, [esp+8]
mov ebp, [esp+12]
add esp, 28 {Clears Overflow flag}
ret 8
@@CheckRange:
jne @@Overflow {Overflow if edx>$80000000}
test esi, esi {edx=$80000000, Is Sign Flag=0?}
jnz @@SetSign {No, Result is Ok (-MaxInt64)}
@@Overflow:
mov ebx, [esp] {restore used registers}
mov esi, [esp+4]
mov edi, [esp+8]
mov ebp, [esp+12]
add esp, 28
mov ecx, $80000000
dec ecx {Set Overflow Flag}
ret 8
end;