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- /* Division and remainder routines for Tile.
- Copyright (C) 2011-2022 Free Software Foundation, Inc.
- Contributed by Walter Lee (walt@tilera.com)
- 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 int int32_t;
- typedef unsigned uint32_t;
- typedef long long int64_t;
- typedef unsigned long long uint64_t;
- /* Raise signal 8 (SIGFPE) with code 1 (FPE_INTDIV). */
- static inline void
- raise_intdiv (void)
- {
- asm ("{ raise; moveli zero, 8 + (1 << 6) }");
- }
- #ifndef __tilegx__
- /*__udivsi3 - 32 bit integer unsigned divide */
- static inline uint32_t __attribute__ ((always_inline))
- __udivsi3_inline (uint32_t dividend, uint32_t divisor)
- {
- /* Divide out any power of two factor from dividend and divisor.
- Note that when dividing by zero the divisor will remain zero,
- which is all we need to detect that case below. */
- const int power_of_two_factor = __insn_ctz (divisor);
- divisor >>= power_of_two_factor;
- dividend >>= power_of_two_factor;
- /* Checks for division by power of two or division by zero. */
- if (divisor <= 1)
- {
- if (divisor == 0)
- {
- raise_intdiv ();
- return 0;
- }
- return dividend;
- }
- /* Compute (a / b) by repeatedly finding the largest N
- such that (b << N) <= a. For each such N, set bit N in the
- quotient, subtract (b << N) from a, and keep going. Think of this as
- the reverse of the "shift-and-add" that a multiply does. The values
- of N are precisely those shift counts.
- Finding N is easy. First, use clz(b) - clz(a) to find the N
- that lines up the high bit of (b << N) with the high bit of a.
- Any larger value of N would definitely make (b << N) > a,
- which is too big.
- Then, if (b << N) > a (because it has larger low bits), decrement
- N by one. This adjustment will definitely make (b << N) less
- than a, because a's high bit is now one higher than b's. */
- /* Precomputing the max_ values allows us to avoid a subtract
- in the inner loop and just right shift by clz(remainder). */
- const int divisor_clz = __insn_clz (divisor);
- const uint32_t max_divisor = divisor << divisor_clz;
- const uint32_t max_qbit = 1 << divisor_clz;
- uint32_t quotient = 0;
- uint32_t remainder = dividend;
- while (remainder >= divisor)
- {
- int shift = __insn_clz (remainder);
- uint32_t scaled_divisor = max_divisor >> shift;
- uint32_t quotient_bit = max_qbit >> shift;
- int too_big = (scaled_divisor > remainder);
- scaled_divisor >>= too_big;
- quotient_bit >>= too_big;
- remainder -= scaled_divisor;
- quotient |= quotient_bit;
- }
- return quotient;
- }
- #endif /* !__tilegx__ */
- /* __udivdi3 - 64 bit integer unsigned divide */
- static inline uint64_t __attribute__ ((always_inline))
- __udivdi3_inline (uint64_t dividend, uint64_t divisor)
- {
- /* Divide out any power of two factor from dividend and divisor.
- Note that when dividing by zero the divisor will remain zero,
- which is all we need to detect that case below. */
- const int power_of_two_factor = __builtin_ctzll (divisor);
- divisor >>= power_of_two_factor;
- dividend >>= power_of_two_factor;
- /* Checks for division by power of two or division by zero. */
- if (divisor <= 1)
- {
- if (divisor == 0)
- {
- raise_intdiv ();
- return 0;
- }
- return dividend;
- }
- #ifndef __tilegx__
- if (((uint32_t) (dividend >> 32) | ((uint32_t) (divisor >> 32))) == 0)
- {
- /* Operands both fit in 32 bits, so use faster 32 bit algorithm. */
- return __udivsi3_inline ((uint32_t) dividend, (uint32_t) divisor);
- }
- #endif /* !__tilegx__ */
- /* See algorithm description in __udivsi3 */
- const int divisor_clz = __builtin_clzll (divisor);
- const uint64_t max_divisor = divisor << divisor_clz;
- const uint64_t max_qbit = 1ULL << divisor_clz;
- uint64_t quotient = 0;
- uint64_t remainder = dividend;
- while (remainder >= divisor)
- {
- int shift = __builtin_clzll (remainder);
- uint64_t scaled_divisor = max_divisor >> shift;
- uint64_t quotient_bit = max_qbit >> shift;
- int too_big = (scaled_divisor > remainder);
- scaled_divisor >>= too_big;
- quotient_bit >>= too_big;
- remainder -= scaled_divisor;
- quotient |= quotient_bit;
- }
- return quotient;
- }
- #ifndef __tilegx__
- /* __umodsi3 - 32 bit integer unsigned modulo */
- static inline uint32_t __attribute__ ((always_inline))
- __umodsi3_inline (uint32_t dividend, uint32_t divisor)
- {
- /* Shortcircuit mod by a power of two (and catch mod by zero). */
- const uint32_t mask = divisor - 1;
- if ((divisor & mask) == 0)
- {
- if (divisor == 0)
- {
- raise_intdiv ();
- return 0;
- }
- return dividend & mask;
- }
- /* We compute the remainder (a % b) by repeatedly subtracting off
- multiples of b from a until a < b. The key is that subtracting
- off a multiple of b does not affect the result mod b.
- To make the algorithm run efficiently, we need to subtract
- off a large multiple of b at each step. We subtract the largest
- (b << N) that is <= a.
- Finding N is easy. First, use clz(b) - clz(a) to find the N
- that lines up the high bit of (b << N) with the high bit of a.
- Any larger value of N would definitely make (b << N) > a,
- which is too big.
- Then, if (b << N) > a (because it has larger low bits), decrement
- N by one. This adjustment will definitely make (b << N) less
- than a, because a's high bit is now one higher than b's. */
- const uint32_t max_divisor = divisor << __insn_clz (divisor);
- uint32_t remainder = dividend;
- while (remainder >= divisor)
- {
- const int shift = __insn_clz (remainder);
- uint32_t scaled_divisor = max_divisor >> shift;
- scaled_divisor >>= (scaled_divisor > remainder);
- remainder -= scaled_divisor;
- }
- return remainder;
- }
- #endif /* !__tilegx__ */
- /* __umoddi3 - 64 bit integer unsigned modulo */
- static inline uint64_t __attribute__ ((always_inline))
- __umoddi3_inline (uint64_t dividend, uint64_t divisor)
- {
- #ifndef __tilegx__
- if (((uint32_t) (dividend >> 32) | ((uint32_t) (divisor >> 32))) == 0)
- {
- /* Operands both fit in 32 bits, so use faster 32 bit algorithm. */
- return __umodsi3_inline ((uint32_t) dividend, (uint32_t) divisor);
- }
- #endif /* !__tilegx__ */
- /* Shortcircuit mod by a power of two (and catch mod by zero). */
- const uint64_t mask = divisor - 1;
- if ((divisor & mask) == 0)
- {
- if (divisor == 0)
- {
- raise_intdiv ();
- return 0;
- }
- return dividend & mask;
- }
- /* See algorithm description in __umodsi3 */
- const uint64_t max_divisor = divisor << __builtin_clzll (divisor);
- uint64_t remainder = dividend;
- while (remainder >= divisor)
- {
- const int shift = __builtin_clzll (remainder);
- uint64_t scaled_divisor = max_divisor >> shift;
- scaled_divisor >>= (scaled_divisor > remainder);
- remainder -= scaled_divisor;
- }
- return remainder;
- }
- uint32_t __udivsi3 (uint32_t dividend, uint32_t divisor);
- #ifdef L_tile_udivsi3
- uint32_t
- __udivsi3 (uint32_t dividend, uint32_t divisor)
- {
- #ifndef __tilegx__
- return __udivsi3_inline (dividend, divisor);
- #else /* !__tilegx__ */
- uint64_t n = __udivdi3_inline (((uint64_t) dividend), ((uint64_t) divisor));
- return (uint32_t) n;
- #endif /* !__tilegx__ */
- }
- #endif
- #define ABS(x) ((x) >= 0 ? (x) : -(x))
- int32_t __divsi3 (int32_t dividend, int32_t divisor);
- #ifdef L_tile_divsi3
- /* __divsi3 - 32 bit integer signed divide */
- int32_t
- __divsi3 (int32_t dividend, int32_t divisor)
- {
- #ifndef __tilegx__
- uint32_t n = __udivsi3_inline (ABS (dividend), ABS (divisor));
- #else /* !__tilegx__ */
- uint64_t n =
- __udivdi3_inline (ABS ((int64_t) dividend), ABS ((int64_t) divisor));
- #endif /* !__tilegx__ */
- if ((dividend ^ divisor) < 0)
- n = -n;
- return (int32_t) n;
- }
- #endif
- uint64_t __udivdi3 (uint64_t dividend, uint64_t divisor);
- #ifdef L_tile_udivdi3
- uint64_t
- __udivdi3 (uint64_t dividend, uint64_t divisor)
- {
- return __udivdi3_inline (dividend, divisor);
- }
- #endif
- /*__divdi3 - 64 bit integer signed divide */
- int64_t __divdi3 (int64_t dividend, int64_t divisor);
- #ifdef L_tile_divdi3
- int64_t
- __divdi3 (int64_t dividend, int64_t divisor)
- {
- uint64_t n = __udivdi3_inline (ABS (dividend), ABS (divisor));
- if ((dividend ^ divisor) < 0)
- n = -n;
- return (int64_t) n;
- }
- #endif
- uint32_t __umodsi3 (uint32_t dividend, uint32_t divisor);
- #ifdef L_tile_umodsi3
- uint32_t
- __umodsi3 (uint32_t dividend, uint32_t divisor)
- {
- #ifndef __tilegx__
- return __umodsi3_inline (dividend, divisor);
- #else /* !__tilegx__ */
- return __umoddi3_inline ((uint64_t) dividend, (uint64_t) divisor);
- #endif /* !__tilegx__ */
- }
- #endif
- /* __modsi3 - 32 bit integer signed modulo */
- int32_t __modsi3 (int32_t dividend, int32_t divisor);
- #ifdef L_tile_modsi3
- int32_t
- __modsi3 (int32_t dividend, int32_t divisor)
- {
- #ifndef __tilegx__
- uint32_t remainder = __umodsi3_inline (ABS (dividend), ABS (divisor));
- #else /* !__tilegx__ */
- uint64_t remainder =
- __umoddi3_inline (ABS ((int64_t) dividend), ABS ((int64_t) divisor));
- #endif /* !__tilegx__ */
- return (int32_t) ((dividend >= 0) ? remainder : -remainder);
- }
- #endif
- uint64_t __umoddi3 (uint64_t dividend, uint64_t divisor);
- #ifdef L_tile_umoddi3
- uint64_t
- __umoddi3 (uint64_t dividend, uint64_t divisor)
- {
- return __umoddi3_inline (dividend, divisor);
- }
- #endif
- /* __moddi3 - 64 bit integer signed modulo */
- int64_t __moddi3 (int64_t dividend, int64_t divisor);
- #ifdef L_tile_moddi3
- int64_t
- __moddi3 (int64_t dividend, int64_t divisor)
- {
- uint64_t remainder = __umoddi3_inline (ABS (dividend), ABS (divisor));
- return (int64_t) ((dividend >= 0) ? remainder : -remainder);
- }
- #endif
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