| //===-- divmodsi4.S - 32-bit signed integer divide and modulus ------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements the __divmodsi4 (32-bit signed integer divide and |
| // modulus) function for the ARM architecture. A naive digit-by-digit |
| // computation is employed for simplicity. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "../assembly.h" |
| |
| #define ESTABLISH_FRAME \ |
| push {r4-r7, lr} ;\ |
| add r7, sp, #12 |
| #define CLEAR_FRAME_AND_RETURN \ |
| pop {r4-r7, pc} |
| |
| .syntax unified |
| .text |
| DEFINE_CODE_STATE |
| |
| @ int __divmodsi4(int divident, int divisor, int *remainder) |
| @ Calculate the quotient and remainder of the (signed) division. The return |
| @ value is the quotient, the remainder is placed in the variable. |
| |
| .p2align 3 |
| DEFINE_COMPILERRT_FUNCTION(__divmodsi4) |
| #if __ARM_ARCH_EXT_IDIV__ |
| tst r1, r1 |
| beq LOCAL_LABEL(divzero) |
| mov r3, r0 |
| sdiv r0, r3, r1 |
| mls r1, r0, r1, r3 |
| str r1, [r2] |
| bx lr |
| LOCAL_LABEL(divzero): |
| mov r0, #0 |
| bx lr |
| #else |
| ESTABLISH_FRAME |
| // Set aside the sign of the quotient and modulus, and the address for the |
| // modulus. |
| eor r4, r0, r1 |
| mov r5, r0 |
| mov r6, r2 |
| // Take the absolute value of a and b via abs(x) = (x^(x >> 31)) - (x >> 31). |
| eor ip, r0, r0, asr #31 |
| eor lr, r1, r1, asr #31 |
| sub r0, ip, r0, asr #31 |
| sub r1, lr, r1, asr #31 |
| // Unsigned divmod: |
| bl SYMBOL_NAME(__udivmodsi4) |
| // Apply the sign of quotient and modulus |
| ldr r1, [r6] |
| eor r0, r0, r4, asr #31 |
| eor r1, r1, r5, asr #31 |
| sub r0, r0, r4, asr #31 |
| sub r1, r1, r5, asr #31 |
| str r1, [r6] |
| CLEAR_FRAME_AND_RETURN |
| #endif |
| END_COMPILERRT_FUNCTION(__divmodsi4) |
| |
| NO_EXEC_STACK_DIRECTIVE |
| |
