sambuc/retrobsd
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Fixes with aliasing - using ieee.h

Browse Source
This commit is contained in:
igor-m
2014-04-12 13:39:05 +02:00
parent 190aa1e633
commit 297b14aa0c
1 changed files with 8 additions and 34 deletions
Download Patch File Download Diff File Expand all files Collapse all files

42
src/libc/gen/modf.c
View File

@@ -7,26 +7,7 @@
* is preserved.
*/
#include <math.h>
// IM: dereferencing type-punned pointer will break strict-aliasing rules
// TODO check Endiannes
union {
double d64;
struct { long i32h;
long i32l;
};
} ew;
/* Get two 32 bit ints from a double. */
//#define EXTRACT_WORDS(high,low,d)
// high = *(unsigned long long*) &d;
// low = (*(unsigned long long*) &d) >> 32
/* Set a double from two 32 bit ints. */
#define INSERT_WORDS(d,high,low) \
*(unsigned long long*) &(x) = (unsigned long long) (high) << 32 | (low)
#include <ieee.h>
/*
* modf(double x, double *iptr)
@@ -44,14 +25,12 @@ double modf (double x, double *iptr)
long i0, i1, j0;
unsigned long i;
//EXTRACT_WORDS (i0, i1, x);
ew.d64 = x; i0 = ew.i32h; i1 = ew.i32l;
EXTRACT_WORDS (i0, i1, x);
//
j0 = ((i0 >> 20) & 0x7ff) - 0x3ff; /* exponent of x */
if (j0 < 20) { /* integer part in high x */
if (j0 < 0) { /* |x|<1 */
//INSERT_WORDS (*iptr, i0 & 0x80000000, 0);
ew.i32h = i0 & 0x80000000; ew.i32l = 0; *iptr = ew.d64;
INSERT_WORDS (*iptr, i0 & 0x80000000, 0);
//
/* *iptr = +-0 */
return x;
@@ -59,14 +38,12 @@ double modf (double x, double *iptr)
i = (0x000fffff) >> j0;
if (((i0 & i) | i1) == 0) { /* x is integral */
*iptr = x;
//INSERT_WORDS (x, i0 & 0x80000000, 0);
ew.i32h = i0 & 0x80000000; ew.i32l = 0; x = ew.d64;
INSERT_WORDS (x, i0 & 0x80000000, 0);
//
/* return +-0 */
return x;
} else {
//INSERT_WORDS (*iptr, i0 & (~i), 0);
ew.i32h = i0 & (~i); ew.i32l = 0; *iptr = ew.d64;
INSERT_WORDS (*iptr, i0 & (~i), 0);
//
return x - *iptr;
}
@@ -77,8 +54,7 @@ double modf (double x, double *iptr)
if (j0 == 0x400 && ((i0 & 0xfffff) | i1))
return x * one;
//INSERT_WORDS (x, i0 & 0x80000000, 0);
ew.i32h = i0 & 0x80000000; ew.i32l = 0; x = ew.d64;
INSERT_WORDS (x, i0 & 0x80000000, 0);
//
/* return +-0 */
return x;
@@ -86,14 +62,12 @@ double modf (double x, double *iptr)
i = ((unsigned long) (0xffffffff)) >> (j0 - 20);
if ((i1 & i) == 0) { /* x is integral */
*iptr = x;
//INSERT_WORDS (x, i0 & 0x80000000, 0);
ew.i32h = i0 & 0x80000000; ew.i32l = 0; x = ew.d64;
INSERT_WORDS (x, i0 & 0x80000000, 0);
//
/* return +-0 */
return x;
} else {
//INSERT_WORDS (*iptr, i0, i1 & (~i));
ew.i32h = i0; ew.i32l = i1 & (~i); *iptr = ew.d64;
INSERT_WORDS (*iptr, i0, i1 & (~i));
//
return x - *iptr;
}