Ekdohibs
/
zig
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Add more compiler-rt functions for ARM platform

master
LemonBoy 2020-01-04 11:55:19 +01:00 committed by Andrew Kelley
parent d3d77138ec
commit e3a63b4e5a
3 changed files with 144 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
lib/std/special/compiler_rt.zig
View File

@ -75,6 +75,9 @@ comptime {
@export("__floatsisf", @import("compiler_rt/floatsiXf.zig").__floatsisf, linkage);
@export("__floatdidf", @import("compiler_rt/floatdidf.zig").__floatdidf, linkage);
@export("__floatsitf", @import("compiler_rt/floatsiXf.zig").__floatsitf, linkage);
@export("__floatunsisf", @import("compiler_rt/floatunsisf.zig").__floatunsisf, linkage);
@export("__floatundisf", @import("compiler_rt/floatundisf.zig").__floatundisf, linkage);
@export("__floatunsidf", @import("compiler_rt/floatunsidf.zig").__floatunsidf, linkage);
@export("__floatundidf", @import("compiler_rt/floatundidf.zig").__floatundidf, linkage);
@ -183,6 +186,8 @@ comptime {
@export("__aeabi_l2d", @import("compiler_rt/floatdidf.zig").__floatdidf, linkage);
@export("__aeabi_ui2d", @import("compiler_rt/floatunsidf.zig").__floatunsidf, linkage);
@export("__aeabi_ul2d", @import("compiler_rt/floatundidf.zig").__floatundidf, linkage);
@export("__aeabi_ui2f", @import("compiler_rt/floatunsisf.zig").__floatunsisf, linkage);
@export("__aeabi_ul2f", @import("compiler_rt/floatundisf.zig").__floatundisf, linkage);
@export("__aeabi_fneg", @import("compiler_rt/negXf2.zig").__negsf2, linkage);
@export("__aeabi_dneg", @import("compiler_rt/negXf2.zig").__negdf2, linkage);

86
lib/std/special/compiler_rt/floatundisf.zig Normal file
View File

@ -0,0 +1,86 @@
const builtin = @import("builtin");
const std = @import("std");
const maxInt = std.math.maxInt;
const FLT_MANT_DIG = 24;
pub extern fn __floatundisf(arg: u64) f32 {
@setRuntimeSafety(builtin.is_test);
if (arg == 0) return 0;
var a = arg;
const N: usize = @TypeOf(a).bit_count;
// Number of significant digits
const sd = N - @clz(u64, a);
// 8 exponent
var e = @intCast(u32, sd) - 1;
if (sd > FLT_MANT_DIG) {
// start: 0000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQxxxxxxxxxxxxxxxxxx
// finish: 000000000000000000000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQR
// 12345678901234567890123456
// 1 = msb 1 bit
// P = bit FLT_MANT_DIG-1 bits to the right of 1
// Q = bit FLT_MANT_DIG bits to the right of 1
// R = "or" of all bits to the right of Q
switch (sd) {
FLT_MANT_DIG + 1 => a <<= 1,
FLT_MANT_DIG + 2 => {},
else => {
const shift_amt = @intCast(u6, ((N + FLT_MANT_DIG + 2) - sd));
const all_ones: u64 = maxInt(u64);
a = (a >> @intCast(u6, sd - (FLT_MANT_DIG + 2))) |
@boolToInt(a & (all_ones >> shift_amt) != 0);
},
}
// Or P into R
a |= @boolToInt((a & 4) != 0);
// round - this step may add a significant bit
a += 1;
// dump Q and R
a >>= 2;
// a is now rounded to FLT_MANT_DIG or FLT_MANT_DIG+1 bits
if ((a & (@as(u64, 1) << FLT_MANT_DIG)) != 0) {
a >>= 1;
e += 1;
}
// a is now rounded to FLT_MANT_DIG bits
} else {
a <<= @intCast(u6, FLT_MANT_DIG - sd);
// a is now rounded to FLT_MANT_DIG bits
}
const result: u32 = ((e + 127) << 23) | // exponent
@truncate(u32, a & 0x007FFFFF); // mantissa
return @bitCast(f32, result);
}
fn test__floatundisf(a: u64, expected: f32) void {
std.testing.expectEqual(expected, __floatundisf(a));
}
test "floatundisf" {
test__floatundisf(0, 0.0);
test__floatundisf(1, 1.0);
test__floatundisf(2, 2.0);
test__floatundisf(0x7FFFFF8000000000, 0x1.FFFFFEp+62F);
test__floatundisf(0x7FFFFF0000000000, 0x1.FFFFFCp+62F);
test__floatundisf(0x8000008000000000, 0x1p+63F);
test__floatundisf(0x8000010000000000, 0x1.000002p+63F);
test__floatundisf(0x8000000000000000, 0x1p+63F);
test__floatundisf(0x8000000000000001, 0x1p+63F);
test__floatundisf(0xFFFFFFFFFFFFFFFE, 0x1p+64F);
test__floatundisf(0xFFFFFFFFFFFFFFFF, 0x1p+64F);
test__floatundisf(0x0007FB72E8000000, 0x1.FEDCBAp+50F);
test__floatundisf(0x0007FB72EA000000, 0x1.FEDCBAp+50F);
test__floatundisf(0x0007FB72EB000000, 0x1.FEDCBAp+50F);
test__floatundisf(0x0007FB72EBFFFFFF, 0x1.FEDCBAp+50F);
test__floatundisf(0x0007FB72EC000000, 0x1.FEDCBCp+50F);
test__floatundisf(0x0007FB72E8000001, 0x1.FEDCBAp+50F);
test__floatundisf(0x0007FB72E6000000, 0x1.FEDCBAp+50F);
test__floatundisf(0x0007FB72E7000000, 0x1.FEDCBAp+50F);
test__floatundisf(0x0007FB72E7FFFFFF, 0x1.FEDCBAp+50F);
test__floatundisf(0x0007FB72E4000001, 0x1.FEDCBAp+50F);
test__floatundisf(0x0007FB72E4000000, 0x1.FEDCB8p+50F);
}

53
lib/std/special/compiler_rt/floatunsisf.zig Normal file
View File

@ -0,0 +1,53 @@
const builtin = @import("builtin");
const std = @import("std");
const maxInt = std.math.maxInt;
const significandBits = 23;
const exponentBias = 127;
const implicitBit = @as(u32, 1) << significandBits;
pub extern fn __floatunsisf(arg: u32) f32 {
@setRuntimeSafety(builtin.is_test);
if (arg == 0) return 0.0;
// The exponent is the width of abs(a)
const exp = @as(u32, 31) - @clz(u32, arg);
var mantissa: u32 = undefined;
if (exp <= significandBits) {
// Shift a into the significand field and clear the implicit bit
const shift = @intCast(u5, significandBits - exp);
mantissa = @as(u32, arg) << shift ^ implicitBit;
} else {
const shift = @intCast(u5, exp - significandBits);
// Round to the nearest number after truncation
mantissa = @as(u32, arg) >> shift ^ implicitBit;
// Align to the left and check if the truncated part is halfway over
const round = arg << @intCast(u5, 31 - shift);
mantissa += @boolToInt(round > 0x80000000);
// Tie to even
mantissa += mantissa & 1;
}
// Use the addition instead of a or since we may have a carry from the
// mantissa to the exponent
var result = mantissa;
result += (exp + exponentBias) << significandBits;
return @bitCast(f32, result);
}
fn test_one_floatunsisf(a: u32, expected: u32) void {
const r = __floatunsisf(a);
std.testing.expect(@bitCast(u32, r) == expected);
}
test "floatunsisf" {
// Test the produced bit pattern
test_one_floatunsisf(0, 0);
test_one_floatunsisf(1, 0x3f800000);
test_one_floatunsisf(0x7FFFFFFF, 0x4f000000);
test_one_floatunsisf(0x80000000, 0x4f000000);
test_one_floatunsisf(0xFFFFFFFF, 0x4f800000);
}