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[/] [openrisc/] [tags/] [gnu-src/] [gcc-4.5.1/] [gcc-4.5.1-or32-1.0rc4/] [gcc/] [config/] [cris/] [arit.c] - Rev 519
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/* Signed and unsigned multiplication and division and modulus for CRIS. Contributed by Axis Communications. Written by Hans-Peter Nilsson <hp@axis.se>, c:a 1992. Copyright (C) 1998, 1999, 2000, 2001, 2002, 2005, 2009 Free Software Foundation, Inc. This file is part of GCC. GCC 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/>. */ /* Note that we provide prototypes for all "const" functions, to attach the const attribute. This is necessary in 2.7.2 - adding the attribute to the function *definition* is a syntax error. This did not work with e.g. 2.1; back then, the return type had to be "const". */ #include "config.h" #if defined (__CRIS_arch_version) && __CRIS_arch_version >= 3 #define LZ(v) __builtin_clz (v) #endif #if defined (L_udivsi3) || defined (L_divsi3) || defined (L_umodsi3) \ || defined (L_modsi3) /* Result type of divmod worker function. */ struct quot_rem { long quot; long rem; }; /* This is the worker function for div and mod. It is inlined into the respective library function. Parameter A must have bit 31 == 0. */ static __inline__ struct quot_rem do_31div (unsigned long a, unsigned long b) __attribute__ ((__const__, __always_inline__)); static __inline__ struct quot_rem do_31div (unsigned long a, unsigned long b) { /* Adjust operands and result if a is 31 bits. */ long extra = 0; int quot_digits = 0; if (b == 0) { struct quot_rem ret; ret.quot = 0xffffffff; ret.rem = 0xffffffff; return ret; } if (a < b) return (struct quot_rem) { 0, a }; #ifdef LZ if (b <= a) { quot_digits = LZ (b) - LZ (a); quot_digits += (a >= (b << quot_digits)); b <<= quot_digits; } #else while (b <= a) { b <<= 1; quot_digits++; } #endif /* Is a 31 bits? Note that bit 31 is handled by the caller. */ if (a & 0x40000000) { /* Then make b:s highest bit max 0x40000000, because it must have been 0x80000000 to be 1 bit higher than a. */ b >>= 1; /* Adjust a to be maximum 0x3fffffff, i.e. two upper bits zero. */ if (a >= b) { a -= b; extra = 1 << (quot_digits - 1); } else { a -= b >> 1; /* Remember that we adjusted a by subtracting b * 2 ** Something. */ extra = 1 << quot_digits; } /* The number of quotient digits will be one less, because we just adjusted b. */ quot_digits--; } /* Now do the division part. */ /* Subtract b and add ones to the right when a >= b i.e. "a - (b - 1) == (a - b) + 1". */ b--; #define DS __asm__ ("dstep %2,%0" : "=r" (a) : "0" (a), "r" (b)) switch (quot_digits) { case 32: DS; case 31: DS; case 30: DS; case 29: DS; case 28: DS; case 27: DS; case 26: DS; case 25: DS; case 24: DS; case 23: DS; case 22: DS; case 21: DS; case 20: DS; case 19: DS; case 18: DS; case 17: DS; case 16: DS; case 15: DS; case 14: DS; case 13: DS; case 12: DS; case 11: DS; case 10: DS; case 9: DS; case 8: DS; case 7: DS; case 6: DS; case 5: DS; case 4: DS; case 3: DS; case 2: DS; case 1: DS; case 0:; } { struct quot_rem ret; ret.quot = (a & ((1 << quot_digits) - 1)) + extra; ret.rem = a >> quot_digits; return ret; } } #ifdef L_udivsi3 unsigned long __Udiv (unsigned long a, unsigned long b) __attribute__ ((__const__)); unsigned long __Udiv (unsigned long a, unsigned long b) { long extra = 0; /* Adjust operands and result, if a and/or b is 32 bits. */ /* Effectively: b & 0x80000000. */ if ((long) b < 0) return a >= b; /* Effectively: a & 0x80000000. */ if ((long) a < 0) { int tmp = 0; if (b == 0) return 0xffffffff; #ifdef LZ tmp = LZ (b); #else for (tmp = 31; (((long) b & (1 << tmp)) == 0); tmp--) ; tmp = 31 - tmp; #endif if ((b << tmp) > a) { extra = 1 << (tmp-1); a -= b << (tmp - 1); } else { extra = 1 << tmp; a -= b << tmp; } } return do_31div (a, b).quot+extra; } #endif /* L_udivsi3 */ #ifdef L_divsi3 long __Div (long a, long b) __attribute__ ((__const__)); long __Div (long a, long b) { long extra = 0; long sign = (b < 0) ? -1 : 1; /* We need to handle a == -2147483648 as expected and must while doing that avoid producing a sequence like "abs (a) < 0" as GCC may optimize out the test. That sequence may not be obvious as we call inline functions. Testing for a being negative and handling (presumably much rarer than positive) enables us to get a bit of optimization for an (accumulated) reduction of the penalty of the 0x80000000 special-case. */ if (a < 0) { sign = -sign; if ((a & 0x7fffffff) == 0) { /* We're at 0x80000000. Tread carefully. */ a -= b * sign; extra = sign; } a = -a; } /* We knowingly penalize pre-v10 models by multiplication with the sign. */ return sign * do_31div (a, __builtin_labs (b)).quot + extra; } #endif /* L_divsi3 */ #ifdef L_umodsi3 unsigned long __Umod (unsigned long a, unsigned long b) __attribute__ ((__const__)); unsigned long __Umod (unsigned long a, unsigned long b) { /* Adjust operands and result if a and/or b is 32 bits. */ if ((long) b < 0) return a >= b ? a - b : a; if ((long) a < 0) { int tmp = 0; if (b == 0) return a; #ifdef LZ tmp = LZ (b); #else for (tmp = 31; (((long) b & (1 << tmp)) == 0); tmp--) ; tmp = 31 - tmp; #endif if ((b << tmp) > a) { a -= b << (tmp - 1); } else { a -= b << tmp; } } return do_31div (a, b).rem; } #endif /* L_umodsi3 */ #ifdef L_modsi3 long __Mod (long a, long b) __attribute__ ((__const__)); long __Mod (long a, long b) { long sign = 1; /* We need to handle a == -2147483648 as expected and must while doing that avoid producing a sequence like "abs (a) < 0" as GCC may optimize out the test. That sequence may not be obvious as we call inline functions. Testing for a being negative and handling (presumably much rarer than positive) enables us to get a bit of optimization for an (accumulated) reduction of the penalty of the 0x80000000 special-case. */ if (a < 0) { sign = -1; if ((a & 0x7fffffff) == 0) /* We're at 0x80000000. Tread carefully. */ a += __builtin_labs (b); a = -a; } return sign * do_31div (a, __builtin_labs (b)).rem; } #endif /* L_modsi3 */ #endif /* L_udivsi3 || L_divsi3 || L_umodsi3 || L_modsi3 */ /* * Local variables: * eval: (c-set-style "gnu") * indent-tabs-mode: t * End: */