mirror of
https://github.com/fluencelabs/musl
synced 2025-06-29 22:51:55 +00:00
ee2ee92d62
* results are exact * modfl follows truncl (raises inexact flag spuriously now) * modf and modff only had cosmetic cleanup * remainder is just a wrapper around remquo now * using iterative shift+subtract for remquo and fmod * ld80 and ld128 are supported as well
66 lines
1.1 KiB
C
66 lines
1.1 KiB
C
#include <math.h>
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#include <stdint.h>
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float fmodf(float x, float y)
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{
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union {float f; uint32_t i;} ux = {x}, uy = {y};
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int ex = ux.i>>23 & 0xff;
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int ey = uy.i>>23 & 0xff;
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uint32_t sx = ux.i & 0x80000000;
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uint32_t i;
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uint32_t uxi = ux.i;
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if (uy.i<<1 == 0 || isnan(y) || ex == 0xff)
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return (x*y)/(x*y);
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if (uxi<<1 <= uy.i<<1) {
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if (uxi<<1 == uy.i<<1)
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return 0*x;
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return x;
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}
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/* normalize x and y */
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if (!ex) {
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for (i = uxi<<9; i>>31 == 0; ex--, i <<= 1);
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uxi <<= -ex + 1;
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} else {
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uxi &= -1U >> 9;
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uxi |= 1U << 23;
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}
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if (!ey) {
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for (i = uy.i<<9; i>>31 == 0; ey--, i <<= 1);
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uy.i <<= -ey + 1;
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} else {
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uy.i &= -1U >> 9;
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uy.i |= 1U << 23;
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}
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/* x mod y */
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for (; ex > ey; ex--) {
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i = uxi - uy.i;
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if (i >> 31 == 0) {
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if (i == 0)
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return 0*x;
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uxi = i;
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}
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uxi <<= 1;
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}
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i = uxi - uy.i;
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if (i >> 31 == 0) {
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if (i == 0)
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return 0*x;
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uxi = i;
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}
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for (; uxi>>23 == 0; uxi <<= 1, ex--);
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/* scale result up */
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if (ex > 0) {
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uxi -= 1U << 23;
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uxi |= (uint32_t)ex << 23;
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} else {
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uxi >>= -ex + 1;
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}
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uxi |= sx;
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ux.i = uxi;
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return ux.f;
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}
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