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Diffstat (limited to 'contrib/compiler-rt/lib/arm/udivmodsi4.S')
| -rw-r--r-- | contrib/compiler-rt/lib/arm/udivmodsi4.S | 80 |
1 files changed, 0 insertions, 80 deletions
diff --git a/contrib/compiler-rt/lib/arm/udivmodsi4.S b/contrib/compiler-rt/lib/arm/udivmodsi4.S deleted file mode 100644 index d164a75..0000000 --- a/contrib/compiler-rt/lib/arm/udivmodsi4.S +++ /dev/null @@ -1,80 +0,0 @@ -/*===-- 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 architecture. A naive digit-by-digit - * computation is employed for simplicity. - * - *===----------------------------------------------------------------------===*/ - -#include "../assembly.h" - -#define ESTABLISH_FRAME \ - push {r4, r7, lr} ;\ - add r7, sp, #4 -#define CLEAR_FRAME_AND_RETURN \ - pop {r4, r7, pc} - -#define a r0 -#define b r1 -#define i r3 -#define r r4 -#define q ip -#define one lr - -.syntax unified -.align 3 -DEFINE_COMPILERRT_FUNCTION(__udivmodsi4) -// We use a simple digit by digit algorithm; before we get into the actual -// divide loop, we must calculate the left-shift amount necessary to align -// the MSB of the divisor with that of the dividend (If this shift is -// negative, then the result is zero, and we early out). We also conjure a -// bit mask of 1 to use in constructing the quotient, and initialize the -// quotient to zero. - ESTABLISH_FRAME - clz r4, a - tst b, b // detect divide-by-zero - clz r3, b - mov q, #0 - beq LOCAL_LABEL(return) // return 0 if b is zero. - mov one, #1 - subs i, r3, r4 - blt LOCAL_LABEL(return) // return 0 if MSB(a) < MSB(b) - -LOCAL_LABEL(mainLoop): -// This loop basically implements the following: -// -// do { -// if (a >= b << i) { -// a -= b << i; -// q |= 1 << i; -// if (a == 0) break; -// } -// } while (--i) -// -// Note that this does not perform the final iteration (i == 0); by doing it -// this way, we can merge the two branches which is a substantial win for -// such a tight loop on current ARM architectures. - subs r, a, b, lsl i - orrhs q, q,one, lsl i - movhs a, r - subsne i, i, #1 - bhi LOCAL_LABEL(mainLoop) - -// Do the final test subtraction and update of quotient (i == 0), as it is -// not performed in the main loop. - subs r, a, b - orrhs q, #1 - movhs a, r - -LOCAL_LABEL(return): -// Store the remainder, and move the quotient to r0, then return. - str a, [r2] - mov r0, q - CLEAR_FRAME_AND_RETURN |
