diff options
Diffstat (limited to 'lib/builtins/arm/udivmodsi4.S')
| -rw-r--r-- | lib/builtins/arm/udivmodsi4.S | 62 |
1 files changed, 30 insertions, 32 deletions
diff --git a/lib/builtins/arm/udivmodsi4.S b/lib/builtins/arm/udivmodsi4.S index ee3950c9b..0f40575fe 100644 --- a/lib/builtins/arm/udivmodsi4.S +++ b/lib/builtins/arm/udivmodsi4.S @@ -1,16 +1,15 @@ -/*===-- udivmodsi4.S - 32-bit unsigned integer divide and modulus ---------===// - * - * The LLVM Compiler Infrastructure - * - * This file is dual licensed under the MIT and the University of Illinois Open - * Source Licenses. See LICENSE.TXT for details. - * - *===----------------------------------------------------------------------===// - * - * This file implements the __udivmodsi4 (32-bit unsigned integer divide and - * modulus) function for the ARM 32-bit architecture. - * - *===----------------------------------------------------------------------===*/ +//===-- udivmodsi4.S - 32-bit unsigned 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 __udivmodsi4 (32-bit unsigned integer divide and +// modulus) function for the ARM 32-bit architecture. +// +//===----------------------------------------------------------------------===// #include "../assembly.h" @@ -39,26 +38,25 @@ DEFINE_COMPILERRT_FUNCTION(__udivmodsi4) beq LOCAL_LABEL(divby1) cmp r0, r1 bcc LOCAL_LABEL(quotient0) - /* - * Implement division using binary long division algorithm. - * - * r0 is the numerator, r1 the denominator. - * - * The code before JMP computes the correct shift I, so that - * r0 and (r1 << I) have the highest bit set in the same position. - * At the time of JMP, ip := .Ldiv0block - 12 * I. - * This depends on the fixed instruction size of block. - * For ARM mode, this is 12 Bytes, for THUMB mode 14 Bytes. - * - * block(shift) implements the test-and-update-quotient core. - * It assumes (r0 << shift) can be computed without overflow and - * that (r0 << shift) < 2 * r1. The quotient is stored in r3. - */ + + // Implement division using binary long division algorithm. + // + // r0 is the numerator, r1 the denominator. + // + // The code before JMP computes the correct shift I, so that + // r0 and (r1 << I) have the highest bit set in the same position. + // At the time of JMP, ip := .Ldiv0block - 12 * I. + // This depends on the fixed instruction size of block. + // For ARM mode, this is 12 Bytes, for THUMB mode 14 Bytes. + // + // block(shift) implements the test-and-update-quotient core. + // It assumes (r0 << shift) can be computed without overflow and + // that (r0 << shift) < 2 * r1. The quotient is stored in r3. # ifdef __ARM_FEATURE_CLZ clz ip, r0 clz r3, r1 - /* r0 >= r1 implies clz(r0) <= clz(r1), so ip <= r3. */ + // r0 >= r1 implies clz(r0) <= clz(r1), so ip <= r3. sub r3, r3, ip # if defined(USE_THUMB_2) adr ip, LOCAL_LABEL(div0block) + 1 @@ -99,11 +97,11 @@ DEFINE_COMPILERRT_FUNCTION(__udivmodsi4) movhs r4, r3 subhs ip, ip, #(2 * 12) - /* Last block, no need to update r3 or r4. */ + // Last block, no need to update r3 or r4. cmp r1, r4, lsr #1 subls ip, ip, #(1 * 12) - ldr r4, [sp], #8 /* restore r4, we are done with it. */ + ldr r4, [sp], #8 // restore r4, we are done with it. mov r3, #0 JMP(ip) @@ -164,7 +162,7 @@ LOCAL_LABEL(divby1): mov r3, #0 str r3, [r2] JMP(lr) -#endif /* __ARM_ARCH_EXT_IDIV__ */ +#endif // __ARM_ARCH_EXT_IDIV__ LOCAL_LABEL(divby0): mov r0, #0 |