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#include "platform.h"
#if HAS_SIGNBIT
C_Int_t Real32_signBit (Real32_t f) {
return signbit (f);
}
C_Int_t Real64_signBit (Real64_t d) {
return signbit (d);
}
#else
enum {
LITTLE_R32_byte = 3,
LITTLE_R64_byte = 7,
};
enum {
BIG_R32_byte = 0,
BIG_R64_byte = 0,
};
C_Int_t Real32_signBit (Real32_t f) {
int R32_byte;
if (isBigEndian()) {
R32_byte = BIG_R32_byte;
} else {
R32_byte = LITTLE_R32_byte;
}
/* Using memcpy.
* Technically correct.
*/
unsigned char chars[4];
memcpy(chars, &f, sizeof(Real32_t));
return (chars[R32_byte] & 0x80) >> 7;
/* Using cast;
* Technically correct, as (unsigned char*) may alias.
*/
/*
return (((unsigned char*)(&f))[R32_byte] & 0x80) >> 7;
*/
/* Using union;
* Technically undefined, but widely supported.
*/
/*
union {float f; unsigned char c[4];} fc;
fc.f = f;
return (fc.c[R32_byte] & 0x80) >> 7;
*/
}
C_Int_t Real64_signBit (Real64_t d) {
int R64_byte;
if (isBigEndian()) {
R64_byte = BIG_R64_byte;
} else {
R64_byte = LITTLE_R64_byte;
}
/* Using memcpy.
* Technically correct.
*/
unsigned char chars[8];
memcpy(chars, &d, sizeof(Real64_t));
return (chars[R64_byte] & 0x80) >> 7;
/* Using cast;
* Technically correct, as (unsigned char*) may alias.
*/
/*
return (((unsigned char*)(&d))[R64_byte] & 0x80) >> 7;
*/
/* Using union;
* Technically undefined, but widely supported.
*/
/*
union {double d; unsigned char c[8];} dc;
dc.d = d;
return (dc.c[R64_byte] & 0x80) >> 7;
*/
}
#endif
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