zig/lib/std/special/compiler_rt/aullrem.zig

78 lines
2.0 KiB
Zig

const builtin = @import("builtin");
pub fn _allrem(a: i64, b: i64) callconv(.Stdcall) i64 {
@setRuntimeSafety(builtin.is_test);
const s_a = a >> (i64.bit_count - 1);
const s_b = b >> (i64.bit_count - 1);
const an = (a ^ s_a) -% s_a;
const bn = (b ^ s_b) -% s_b;
const r = @bitCast(u64, an) % @bitCast(u64, bn);
const s = s_a ^ s_b;
return (@bitCast(i64, r) ^ s) -% s;
}
pub fn _aullrem() callconv(.Naked) void {
@setRuntimeSafety(false);
// The stack layout is:
// ESP+16 divisor (hi)
// ESP+12 divisor (low)
// ESP+8 dividend (hi)
// ESP+4 dividend (low)
// ESP return address
asm volatile (
\\ push %%ebx
\\ mov 0x14(%%esp),%%eax
\\ or %%eax,%%eax
\\ jne 1f
\\ mov 0x10(%%esp),%%ecx
\\ mov 0xc(%%esp),%%eax
\\ xor %%edx,%%edx
\\ div %%ecx
\\ mov 0x8(%%esp),%%eax
\\ div %%ecx
\\ mov %%edx,%%eax
\\ xor %%edx,%%edx
\\ jmp 6f
\\ 1:
\\ mov %%eax,%%ecx
\\ mov 0x10(%%esp),%%ebx
\\ mov 0xc(%%esp),%%edx
\\ mov 0x8(%%esp),%%eax
\\ 2:
\\ shr %%ecx
\\ rcr %%ebx
\\ shr %%edx
\\ rcr %%eax
\\ or %%ecx,%%ecx
\\ jne 2b
\\ div %%ebx
\\ mov %%eax,%%ecx
\\ mull 0x14(%%esp)
\\ xchg %%eax,%%ecx
\\ mull 0x10(%%esp)
\\ add %%ecx,%%edx
\\ jb 3f
\\ cmp 0xc(%%esp),%%edx
\\ ja 3f
\\ jb 4f
\\ cmp 0x8(%%esp),%%eax
\\ jbe 4f
\\ 3:
\\ sub 0x10(%%esp),%%eax
\\ sbb 0x14(%%esp),%%edx
\\ 4:
\\ sub 0x8(%%esp),%%eax
\\ sbb 0xc(%%esp),%%edx
\\ neg %%edx
\\ neg %%eax
\\ sbb $0x0,%%edx
\\ 6:
\\ pop %%ebx
\\ ret $0x10
);
}