diff options
Diffstat (limited to 'compiler-rt/lib/builtins/floattitf.c')
| -rw-r--r-- | compiler-rt/lib/builtins/floattitf.c | 53 |
1 files changed, 25 insertions, 28 deletions
diff --git a/compiler-rt/lib/builtins/floattitf.c b/compiler-rt/lib/builtins/floattitf.c index e9047472e5d..196cbdae14e 100644 --- a/compiler-rt/lib/builtins/floattitf.c +++ b/compiler-rt/lib/builtins/floattitf.c @@ -16,16 +16,14 @@ #include "fp_lib.h" #include "int_lib.h" -/* Returns: convert a ti_int to a fp_t, rounding toward even. */ +// Returns: convert a ti_int to a fp_t, rounding toward even. -/* Assumption: fp_t is a IEEE 128 bit floating point type - * ti_int is a 128 bit integral type - */ +// Assumption: fp_t is a IEEE 128 bit floating point type +// ti_int is a 128 bit integral type -/* seee eeee eeee eeee mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm - * mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm - * mmmm mmmm mmmm - */ +// seee eeee eeee eeee mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm +// mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm +// mmmm mmmm mmmm #if defined(CRT_HAS_128BIT) && defined(CRT_LDBL_128BIT) COMPILER_RT_ABI fp_t __floattitf(ti_int a) { @@ -34,17 +32,16 @@ COMPILER_RT_ABI fp_t __floattitf(ti_int a) { const unsigned N = sizeof(ti_int) * CHAR_BIT; const ti_int s = a >> (N - 1); a = (a ^ s) - s; - int sd = N - __clzti2(a); /* number of significant digits */ - int e = sd - 1; /* exponent */ + int sd = N - __clzti2(a); // number of significant digits + int e = sd - 1; // exponent if (sd > LDBL_MANT_DIG) { - /* start: 0000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQxxxxxxxxxxxxxxxxxx - * finish: 000000000000000000000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQR - * 12345678901234567890123456 - * 1 = msb 1 bit - * P = bit LDBL_MANT_DIG-1 bits to the right of 1 - * Q = bit LDBL_MANT_DIG bits to the right of 1 - * R = "or" of all bits to the right of Q - */ + // start: 0000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQxxxxxxxxxxxxxxxxxx + // finish: 000000000000000000000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQR + // 12345678901234567890123456 + // 1 = msb 1 bit + // P = bit LDBL_MANT_DIG-1 bits to the right of 1 + // Q = bit LDBL_MANT_DIG bits to the right of 1 + // R = "or" of all bits to the right of Q switch (sd) { case LDBL_MANT_DIG + 1: a <<= 1; @@ -55,25 +52,25 @@ COMPILER_RT_ABI fp_t __floattitf(ti_int a) { a = ((tu_int)a >> (sd - (LDBL_MANT_DIG + 2))) | ((a & ((tu_int)(-1) >> ((N + LDBL_MANT_DIG + 2) - sd))) != 0); }; - /* finish: */ - a |= (a & 4) != 0; /* Or P into R */ - ++a; /* round - this step may add a significant bit */ - a >>= 2; /* dump Q and R */ - /* a is now rounded to LDBL_MANT_DIG or LDBL_MANT_DIG+1 bits */ + // finish: + a |= (a & 4) != 0; // Or P into R + ++a; // round - this step may add a significant bit + a >>= 2; // dump Q and R + // a is now rounded to LDBL_MANT_DIG or LDBL_MANT_DIG+1 bits if (a & ((tu_int)1 << LDBL_MANT_DIG)) { a >>= 1; ++e; } - /* a is now rounded to LDBL_MANT_DIG bits */ + // a is now rounded to LDBL_MANT_DIG bits } else { a <<= (LDBL_MANT_DIG - sd); - /* a is now rounded to LDBL_MANT_DIG bits */ + // a is now rounded to LDBL_MANT_DIG bits } long_double_bits fb; - fb.u.high.all = (s & 0x8000000000000000LL) /* sign */ - | (du_int)(e + 16383) << 48 /* exponent */ - | ((a >> 64) & 0x0000ffffffffffffLL); /* significand */ + fb.u.high.all = (s & 0x8000000000000000LL) // sign + | (du_int)(e + 16383) << 48 // exponent + | ((a >> 64) & 0x0000ffffffffffffLL); // significand fb.u.low.all = (du_int)(a); return fb.f; } |
