projects / rustc.git / blame
| Commit | Line | Data |
|---|---|---|
| 1a4d82fc JJ |
1 | /*===-- divmodsi4.S - 32-bit signed integer divide and modulus ------------===// |
| 2 | * | |
| 3 | * The LLVM Compiler Infrastructure | |
| 4 | * | |
| 5 | * This file is dual licensed under the MIT and the University of Illinois Open | |
| 6 | * Source Licenses. See LICENSE.TXT for details. | |
| 7 | * | |
| 8 | *===----------------------------------------------------------------------===// | |
| 9 | * | |
| 10 | * This file implements the __divmodsi4 (32-bit signed integer divide and | |
| 11 | * modulus) function for the ARM architecture. A naive digit-by-digit | |
| 12 | * computation is employed for simplicity. | |
| 13 | * | |
| 14 | *===----------------------------------------------------------------------===*/ | |
| 15 | ||
| 16 | #include "../assembly.h" | |
| 17 | ||
| 18 | #define ESTABLISH_FRAME \ | |
| 19 | push {r4-r7, lr} ;\ | |
| 20 | add r7, sp, #12 | |
| 21 | #define CLEAR_FRAME_AND_RETURN \ | |
| 22 | pop {r4-r7, pc} | |
| 23 | ||
| 92a42be0 SL |
24 | .syntax unified |
| 25 | .text | |
| 2c00a5a8 | 26 | DEFINE_CODE_STATE |
| 92a42be0 SL |
27 | |
| 28 | @ int __divmodsi4(int divident, int divisor, int *remainder) | |
| 29 | @ Calculate the quotient and remainder of the (signed) division. The return | |
| 30 | @ value is the quotient, the remainder is placed in the variable. | |
| 31 | ||
| 32 | .p2align 3 | |
| 1a4d82fc JJ |
33 | DEFINE_COMPILERRT_FUNCTION(__divmodsi4) |
| 34 | #if __ARM_ARCH_EXT_IDIV__ | |
| 35 | tst r1, r1 | |
| 36 | beq LOCAL_LABEL(divzero) | |
| 37 | mov r3, r0 | |
| 38 | sdiv r0, r3, r1 | |
| 39 | mls r1, r0, r1, r3 | |
| 40 | str r1, [r2] | |
| 41 | bx lr | |
| 42 | LOCAL_LABEL(divzero): | |
| 43 | mov r0, #0 | |
| 44 | bx lr | |
| 45 | #else | |
| 46 | ESTABLISH_FRAME | |
| 47 | // Set aside the sign of the quotient and modulus, and the address for the | |
| 48 | // modulus. | |
| 49 | eor r4, r0, r1 | |
| 50 | mov r5, r0 | |
| 51 | mov r6, r2 | |
| 52 | // Take the absolute value of a and b via abs(x) = (x^(x >> 31)) - (x >> 31). | |
| 53 | eor ip, r0, r0, asr #31 | |
| 54 | eor lr, r1, r1, asr #31 | |
| 55 | sub r0, ip, r0, asr #31 | |
| 56 | sub r1, lr, r1, asr #31 | |
| 57 | // Unsigned divmod: | |
| 58 | bl SYMBOL_NAME(__udivmodsi4) | |
| 59 | // Apply the sign of quotient and modulus | |
| 60 | ldr r1, [r6] | |
| 61 | eor r0, r0, r4, asr #31 | |
| 62 | eor r1, r1, r5, asr #31 | |
| 63 | sub r0, r0, r4, asr #31 | |
| 64 | sub r1, r1, r5, asr #31 | |
| 65 | str r1, [r6] | |
| 66 | CLEAR_FRAME_AND_RETURN | |
| 67 | #endif | |
| 68 | END_COMPILERRT_FUNCTION(__divmodsi4) | |
| 3157f602 XL |
69 | |
| 70 | NO_EXEC_STACK_DIRECTIVE | |
| 71 |