zig/lib/compiler_rt/divmodei4.zig
Jacob Young 917640810e Target: pass and use locals by pointer instead of by value
This struct is larger than 256 bytes and code that copies it
consistently shows up in profiles of the compiler.
2025-06-19 11:45:06 -04:00

52 lines
2 KiB
Zig

const std = @import("std");
const builtin = @import("builtin");
const common = @import("common.zig");
const udivmod = @import("udivmodei4.zig").divmod;
comptime {
@export(&__divei4, .{ .name = "__divei4", .linkage = common.linkage, .visibility = common.visibility });
@export(&__modei4, .{ .name = "__modei4", .linkage = common.linkage, .visibility = common.visibility });
}
const endian = builtin.cpu.arch.endian();
inline fn limb(x: []u32, i: usize) *u32 {
return if (endian == .little) &x[i] else &x[x.len - 1 - i];
}
inline fn neg(x: []u32) void {
var ov: u1 = 1;
for (0..x.len) |limb_index| {
const l = limb(x, limb_index);
l.*, ov = @addWithOverflow(~l.*, ov);
}
}
/// Mutates the arguments!
fn divmod(q: ?[]u32, r: ?[]u32, u: []u32, v: []u32) !void {
const u_sign: i32 = @bitCast(u[u.len - 1]);
const v_sign: i32 = @bitCast(v[v.len - 1]);
if (u_sign < 0) neg(u);
if (v_sign < 0) neg(v);
try @call(.always_inline, udivmod, .{ q, r, u, v });
if (q) |x| if (u_sign ^ v_sign < 0) neg(x);
if (r) |x| if (u_sign < 0) neg(x);
}
pub fn __divei4(q_p: [*]u8, u_p: [*]u8, v_p: [*]u8, bits: usize) callconv(.c) void {
@setRuntimeSafety(builtin.is_test);
const byte_size = std.zig.target.intByteSize(&builtin.target, @intCast(bits));
const q: []u32 = @ptrCast(@alignCast(q_p[0..byte_size]));
const u: []u32 = @ptrCast(@alignCast(u_p[0..byte_size]));
const v: []u32 = @ptrCast(@alignCast(v_p[0..byte_size]));
@call(.always_inline, divmod, .{ q, null, u, v }) catch unreachable;
}
pub fn __modei4(r_p: [*]u8, u_p: [*]u8, v_p: [*]u8, bits: usize) callconv(.c) void {
@setRuntimeSafety(builtin.is_test);
const byte_size = std.zig.target.intByteSize(&builtin.target, @intCast(bits));
const r: []u32 = @ptrCast(@alignCast(r_p[0..byte_size]));
const u: []u32 = @ptrCast(@alignCast(u_p[0..byte_size]));
const v: []u32 = @ptrCast(@alignCast(v_p[0..byte_size]));
@call(.always_inline, divmod, .{ null, r, u, v }) catch unreachable;
}