diff options
Diffstat (limited to 'libgcc/config/epiphany/udivsi3-float.c')
-rw-r--r-- | libgcc/config/epiphany/udivsi3-float.c | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/libgcc/config/epiphany/udivsi3-float.c b/libgcc/config/epiphany/udivsi3-float.c new file mode 100644 index 0000000..c7f1059 --- /dev/null +++ b/libgcc/config/epiphany/udivsi3-float.c @@ -0,0 +1,125 @@ +/* Generic unsigned 32 bit division implementation. + Copyright (C) 2009, 2011 Free Software Foundation, Inc. + Contributed by Embecosm on behalf of Adapteva, Inc. + +This file is part of GCC. + +This file is free software; you can redistribute it and/or modify it +under the terms of the GNU General Public License as published by the +Free Software Foundation; either version 3, or (at your option) any +later version. + +This file is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +General Public License for more details. + +Under Section 7 of GPL version 3, you are granted additional +permissions described in the GCC Runtime Library Exception, version +3.1, as published by the Free Software Foundation. + +You should have received a copy of the GNU General Public License and +a copy of the GCC Runtime Library Exception along with this program; +see the files COPYING3 and COPYING.RUNTIME respectively. If not, see +<http://www.gnu.org/licenses/>. */ + +typedef union { unsigned int i; float f; } fu; + +unsigned int __udivsi3 (unsigned int a, unsigned int b); + +unsigned int +__udivsi3 (unsigned int a, unsigned int b) +{ + unsigned int d, t, s0, s1, s2, r0, r1; + fu u0, u1, u2, u1b, u2b; + + if (b > a) + return 0; + if ((int) b < 0) + return 1; + + /* Assuming B is nonzero, compute S0 such that 0 <= S0, + (B << S0+1) does not overflow, + A < 4.01 * (B << S0), with S0 choosen as small as possible + without taking to much time calculating. */ +#ifdef CONVERT_UNSIGNED + u0.f = a; + u1.f = b; +#else /* !CONVERT_UNSIGNED */ + u0.f = (int) a; + u1.f = (int) b; +#ifdef CONCISE + if (a < 0) + u0.i = (a >> 8) - 0x00800000 + 0x3f800000 + (31 << 23); +#else /* To use flag seting / cmove, this can be written as: */ + { + unsigned c = 0xff800000 - 0x4f000000; + t = (int)a >> 8; + if (t >= c) + u0.i = (t - c); + } +#endif +#endif /* !CONVERT_UNSIGNED */ + s0 = u0.i + 1 /* Compensate for rounding errors. */ + - 0x00800000 /* adjust by one */ ; + s0 = s0 - u1.i; + s0 = (int)s0 >= 0 ? s0 : 0; + s0 >>= 23; + + b <<= s0; + r1 = 0; + + r0 = 1 << s0; + a = ((t=a) - b); + if (a <= t) + { + r1 += r0; + a = ((t=a) - b); + if (a <= t) + do { + r1 += r0; + a = ((t=a) - b); + } while (a <= t); + } + a += b; + d = b - 1; + +#define STEP(n) case n: a += a; t = a - d; if (t <= a) a = t; + switch (s0) + { + STEP (31) + STEP (30) + STEP (29) + STEP (28) + STEP (27) + STEP (26) + STEP (25) + STEP (24) + STEP (23) + STEP (22) + STEP (21) + STEP (20) + STEP (19) + STEP (18) + STEP (17) + STEP (16) + STEP (15) + STEP (14) + STEP (13) + STEP (12) + STEP (11) + STEP (10) + STEP (9) + STEP (8) + STEP (7) + STEP (6) + STEP (5) + STEP (4) + STEP (3) + STEP (2) + STEP (1) + case 0: ; + } + r0 = r1 | (r0-1 & a); + return r0; +} |