0556a2ba53
Finishes cleanups that I started in other commits in this branch. * Use common.linkage for all exports instead of redoing the logic in each file. * Remove pointless `@setRuntimeSafety` calls. * Avoid redundantly exporting multiple versions of functions. For example, if PPC wants `ceilf128` then don't also export `ceilq`; similarly if ARM wants `__aeabi_ddiv` then don't also export `__divdf3`. * Use `inline` for helper functions instead of making inline calls at callsites.
72 lines
1.9 KiB
Zig
72 lines
1.9 KiB
Zig
//! Ported from
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//! https://github.com/llvm/llvm-project/blob/llvmorg-9.0.0/compiler-rt/lib/builtins/muldi3.c
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const std = @import("std");
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const builtin = @import("builtin");
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const native_endian = builtin.cpu.arch.endian();
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const common = @import("common.zig");
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pub const panic = common.panic;
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comptime {
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if (common.want_aeabi) {
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@export(__aeabi_lmul, .{ .name = "__aeabi_lmul", .linkage = common.linkage });
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} else {
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@export(__muldi3, .{ .name = "__muldi3", .linkage = common.linkage });
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}
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}
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pub fn __muldi3(a: i64, b: i64) callconv(.C) i64 {
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return mul(a, b);
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}
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fn __aeabi_lmul(a: i64, b: i64) callconv(.AAPCS) i64 {
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return mul(a, b);
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}
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inline fn mul(a: i64, b: i64) i64 {
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const x = dwords{ .all = a };
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const y = dwords{ .all = b };
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var r = dwords{ .all = muldsi3(x.s.low, y.s.low) };
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r.s.high +%= x.s.high *% y.s.low +% x.s.low *% y.s.high;
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return r.all;
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}
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const dwords = extern union {
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all: i64,
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s: switch (native_endian) {
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.Little => extern struct {
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low: u32,
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high: u32,
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},
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.Big => extern struct {
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high: u32,
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low: u32,
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},
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},
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};
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fn muldsi3(a: u32, b: u32) i64 {
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const bits_in_word_2 = @sizeOf(i32) * 8 / 2;
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const lower_mask = (~@as(u32, 0)) >> bits_in_word_2;
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var r: dwords = undefined;
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r.s.low = (a & lower_mask) *% (b & lower_mask);
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var t: u32 = r.s.low >> bits_in_word_2;
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r.s.low &= lower_mask;
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t += (a >> bits_in_word_2) *% (b & lower_mask);
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r.s.low +%= (t & lower_mask) << bits_in_word_2;
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r.s.high = t >> bits_in_word_2;
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t = r.s.low >> bits_in_word_2;
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r.s.low &= lower_mask;
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t +%= (b >> bits_in_word_2) *% (a & lower_mask);
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r.s.low +%= (t & lower_mask) << bits_in_word_2;
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r.s.high +%= t >> bits_in_word_2;
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r.s.high +%= (a >> bits_in_word_2) *% (b >> bits_in_word_2);
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return r.all;
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}
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test {
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_ = @import("muldi3_test.zig");
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}
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