cosmopolitan/tool/build/lib/x87.c

72 lines
3.1 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ This program is free software; you can redistribute it and/or modify │
│ it under the terms of the GNU General Public License as published by │
│ the Free Software Foundation; version 2 of the License. │
│ │
│ This program is distributed in the hope that it will be useful, but │
│ WITHOUT ANY WARRANTY; without even the implied warranty of │
│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
│ General Public License for more details. │
│ │
│ You should have received a copy of the GNU General Public License │
│ along with this program; if not, write to the Free Software │
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
│ 02110-1301 USA │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "ape/lib/pc.h"
#include "libc/math.h"
#include "tool/build/lib/x87.h"
static long ltruncl(long double x) {
return x;
}
static int ClearC2(int sw) {
return sw & ~FPU_C2;
}
static long double x87remainder(long double x, long double y, uint32_t *sw,
long double rem(long double, long double),
long rnd(long double)) {
int s;
long q;
long double r;
s = 0;
r = rem(x, y);
q = rnd(x / y);
s &= ~FPU_C2; /* ty libm */
if (q & 0b001) s |= FPU_C1;
if (q & 0b010) s |= FPU_C3;
if (q & 0b100) s |= FPU_C0;
if (sw) *sw = s | (*sw & ~(FPU_C0 | FPU_C1 | FPU_C2 | FPU_C3));
return r;
}
long double f2xm1(long double x) {
return exp2l(x) - 1;
}
long double fyl2x(long double x, long double y) {
return y * log2l(x);
}
long double fyl2xp1(long double x, long double y) {
return y * log2l(x + 1);
}
long double fscale(long double significand, long double exponent) {
return scalbl(significand, exponent);
}
long double fprem(long double dividend, long double modulus, uint32_t *sw) {
return x87remainder(dividend, modulus, sw, fmodl, ltruncl);
}
long double fprem1(long double dividend, long double modulus, uint32_t *sw) {
return x87remainder(dividend, modulus, sw, remainderl, lrintl);
}