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Diffstat (limited to 'lib/arm/udivsi3.S')
| -rw-r--r-- | lib/arm/udivsi3.S | 93 |
1 files changed, 0 insertions, 93 deletions
diff --git a/lib/arm/udivsi3.S b/lib/arm/udivsi3.S deleted file mode 100644 index 2bb14123ca317..0000000000000 --- a/lib/arm/udivsi3.S +++ /dev/null @@ -1,93 +0,0 @@ -/*===-- udivsi3.S - 32-bit unsigned integer divide ------------------------===// - * - * 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 __udivsi3 (32-bit unsigned integer divide) - * function for the ARM architecture. A naive digit-by-digit computation is - * employed for simplicity. - * - *===----------------------------------------------------------------------===*/ - -#include "../assembly.h" - -#define ESTABLISH_FRAME \ - push {r7, lr} ;\ - mov r7, sp -#define CLEAR_FRAME_AND_RETURN \ - pop {r7, pc} - -#define a r0 -#define b r1 -#define r r2 -#define i r3 -#define q ip -#define one lr - -.syntax unified -.align 3 -// Ok, APCS and AAPCS agree on 32 bit args, so it's safe to use the same routine. -DEFINE_AEABI_FUNCTION_ALIAS(__aeabi_uidiv, __udivsi3) -DEFINE_COMPILERRT_FUNCTION(__udivsi3) -#if __ARM_ARCH_EXT_IDIV__ - tst r1,r1 - beq LOCAL_LABEL(divzero) - udiv r0, r0, r1 - bx lr - LOCAL_LABEL(divzero): - mov r0,#0 - bx lr -#else -// 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 r2, 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, r2 - 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 - itt hs - orrhs q, q,one, lsl i - movhs a, r - it ne - 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 - it hs - orrhs q, #1 - -LOCAL_LABEL(return): -// Move the quotient to r0 and return. - mov r0, q - CLEAR_FRAME_AND_RETURN -#endif |