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author | dim <dim@FreeBSD.org> | 2015-01-08 19:47:10 +0000 |
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committer | dim <dim@FreeBSD.org> | 2015-01-08 19:47:10 +0000 |
commit | ab328f15cea04a45750ef56019d2b3d971e033f3 (patch) | |
tree | f47eabbd2a48be6d6fec3ddeeefae5b4aeb87dbc /contrib/compiler-rt/lib/builtins/floatdisf.c | |
parent | 8189659be8e499f37c87fdd05ef5ec9f88619d56 (diff) | |
parent | 2f1c5cc1039d86db0037cb086bd58f4b90dc6f66 (diff) | |
download | FreeBSD-src-ab328f15cea04a45750ef56019d2b3d971e033f3.zip FreeBSD-src-ab328f15cea04a45750ef56019d2b3d971e033f3.tar.gz |
Update compiler-rt to trunk r224034. This brings a number of new
builtins, and also the various sanitizers. Support for these will be
added in a later commit.
Diffstat (limited to 'contrib/compiler-rt/lib/builtins/floatdisf.c')
-rw-r--r-- | contrib/compiler-rt/lib/builtins/floatdisf.c | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/contrib/compiler-rt/lib/builtins/floatdisf.c b/contrib/compiler-rt/lib/builtins/floatdisf.c new file mode 100644 index 0000000..3e47580 --- /dev/null +++ b/contrib/compiler-rt/lib/builtins/floatdisf.c @@ -0,0 +1,80 @@ +/*===-- floatdisf.c - Implement __floatdisf -------------------------------=== + * + * The LLVM Compiler Infrastructure + * + * This file is dual licensed under the MIT and the University of Illinois Open + * Source Licenses. See LICENSE.TXT for details. + * + *===----------------------------------------------------------------------=== + * + * This file implements __floatdisf for the compiler_rt library. + * + *===----------------------------------------------------------------------=== + */ + +/* Returns: convert a to a float, rounding toward even.*/ + +/* Assumption: float is a IEEE 32 bit floating point type + * di_int is a 64 bit integral type + */ + +/* seee eeee emmm mmmm mmmm mmmm mmmm mmmm */ + +#include "int_lib.h" + +ARM_EABI_FNALIAS(l2f, floatdisf) + +COMPILER_RT_ABI float +__floatdisf(di_int a) +{ + if (a == 0) + return 0.0F; + const unsigned N = sizeof(di_int) * CHAR_BIT; + const di_int s = a >> (N-1); + a = (a ^ s) - s; + int sd = N - __builtin_clzll(a); /* number of significant digits */ + int e = sd - 1; /* exponent */ + if (sd > FLT_MANT_DIG) + { + /* start: 0000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQxxxxxxxxxxxxxxxxxx + * finish: 000000000000000000000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQR + * 12345678901234567890123456 + * 1 = msb 1 bit + * P = bit FLT_MANT_DIG-1 bits to the right of 1 + * Q = bit FLT_MANT_DIG bits to the right of 1 + * R = "or" of all bits to the right of Q + */ + switch (sd) + { + case FLT_MANT_DIG + 1: + a <<= 1; + break; + case FLT_MANT_DIG + 2: + break; + default: + a = ((du_int)a >> (sd - (FLT_MANT_DIG+2))) | + ((a & ((du_int)(-1) >> ((N + FLT_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 FLT_MANT_DIG or FLT_MANT_DIG+1 bits */ + if (a & ((du_int)1 << FLT_MANT_DIG)) + { + a >>= 1; + ++e; + } + /* a is now rounded to FLT_MANT_DIG bits */ + } + else + { + a <<= (FLT_MANT_DIG - sd); + /* a is now rounded to FLT_MANT_DIG bits */ + } + float_bits fb; + fb.u = ((su_int)s & 0x80000000) | /* sign */ + ((e + 127) << 23) | /* exponent */ + ((su_int)a & 0x007FFFFF); /* mantissa */ + return fb.f; +} |