| 1 | //===-- modsi3.S - 32-bit signed integer modulus --------------------------===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | // |
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| 9 | // This file implements the __modsi3 (32-bit signed integer modulus) function |
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| 10 | // for the ARM architecture as a wrapper around the unsigned routine. |
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| 11 | // |
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| 12 | //===----------------------------------------------------------------------===// |
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| 13 | |
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| 14 | #include "../assembly.h" |
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| 15 | |
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| 16 | #define ESTABLISH_FRAME \ |
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| 17 | push {r4, r7, lr} ;\ |
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| 18 | add r7, sp, #4 |
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| 19 | #define CLEAR_FRAME_AND_RETURN \ |
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| 20 | pop {r4, r7, pc} |
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| 21 | |
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| 22 | .syntax unified |
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| 23 | .text |
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| 24 | DEFINE_CODE_STATE |
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| 25 | |
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| 26 | @ int __modsi3(int divident, int divisor) |
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| 27 | @ Calculate and return the remainder of the (signed) division. |
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| 28 | |
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| 29 | .p2align 3 |
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| 30 | DEFINE_COMPILERRT_FUNCTION(__modsi3) |
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| 31 | #if __ARM_ARCH_EXT_IDIV__ |
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| 32 | tst r1, r1 |
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| 33 | beq LOCAL_LABEL(divzero) |
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| 34 | sdiv r2, r0, r1 |
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| 35 | mls r0, r2, r1, r0 |
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| 36 | bx lr |
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| 37 | LOCAL_LABEL(divzero): |
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| 38 | mov r0, #0 |
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| 39 | bx lr |
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| 40 | #else |
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| 41 | ESTABLISH_FRAME |
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| 42 | // Set aside the sign of the dividend. |
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| 43 | mov r4, r0 |
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| 44 | // Take absolute value of a and b via abs(x) = (x^(x >> 31)) - (x >> 31). |
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| 45 | eor r2, r0, r0, asr #31 |
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| 46 | eor r3, r1, r1, asr #31 |
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| 47 | sub r0, r2, r0, asr #31 |
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| 48 | sub r1, r3, r1, asr #31 |
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| 49 | // abs(a) % abs(b) |
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| 50 | bl SYMBOL_NAME(__umodsi3) |
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| 51 | // Apply sign of dividend to result and return. |
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| 52 | eor r0, r0, r4, asr #31 |
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| 53 | sub r0, r0, r4, asr #31 |
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| 54 | CLEAR_FRAME_AND_RETURN |
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| 55 | #endif |
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| 56 | END_COMPILERRT_FUNCTION(__modsi3) |
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| 57 | |
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| 58 | NO_EXEC_STACK_DIRECTIVE |
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| 59 | |
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| 60 | |
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