zig/lib/compiler_rt/aullrem.zig
Luuk de Gram 30f2bb8464
compiler-rt: Set the symbol visibility
When we're compiling compiler_rt for any WebAssembly target, we do
not want to expose all the compiler-rt functions to the host runtime.
By setting the visibility of all exports to `hidden`, we allow the
linker to resolve the symbols during linktime, while not expose the
functions to the host runtime. This also means the linker can
properly garbage collect any compiler-rt function that does not get
resolved. The symbol visibility for all target remains the same as
before: `default`.
2022-12-28 14:57:17 +01:00

91 lines
2.5 KiB
Zig

const std = @import("std");
const builtin = @import("builtin");
const arch = builtin.cpu.arch;
const abi = builtin.abi;
const common = @import("common.zig");
pub const panic = common.panic;
comptime {
if (arch == .x86 and abi == .msvc) {
// Don't let LLVM apply the stdcall name mangling on those MSVC builtins
@export(_allrem, .{ .name = "\x01__allrem", .linkage = common.linkage, .visibility = common.visibility });
@export(_aullrem, .{ .name = "\x01__aullrem", .linkage = common.linkage, .visibility = common.visibility });
}
}
pub fn _allrem(a: i64, b: i64) callconv(.Stdcall) i64 {
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
);
}