zig/lib/std/special/compiler_rt/aullrem.zig
Andrew Kelley d29871977f remove redundant license headers from zig standard library
We already have a LICENSE file that covers the Zig Standard Library. We
no longer need to remind everyone that the license is MIT in every single
file.

Previously this was introduced to clarify the situation for a fork of
Zig that made Zig's LICENSE file harder to find, and replaced it with
their own license that required annual payments to their company.
However that fork now appears to be dead. So there is no need to
reinforce the copyright notice in every single file.
2021-08-24 12:25:09 -07:00

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 >> (64 - 1);
const s_b = b >> (64 - 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
);
}