| dnl PowerPC-32 mpn_rshift -- Shift a number right. |
| |
| dnl Copyright 1995, 1998, 2000, 2002, 2003, 2004, 2005 Free Software |
| dnl Foundation, Inc. |
| |
| dnl This file is part of the GNU MP Library. |
| |
| dnl The GNU MP Library is free software; you can redistribute it and/or modify |
| dnl it under the terms of the GNU Lesser General Public License as published |
| dnl by the Free Software Foundation; either version 3 of the License, or (at |
| dnl your option) any later version. |
| |
| dnl The GNU MP Library is distributed in the hope that it will be useful, but |
| dnl WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
| dnl or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public |
| dnl License for more details. |
| |
| dnl You should have received a copy of the GNU Lesser General Public License |
| dnl along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. |
| |
| include(`../config.m4') |
| |
| C cycles/limb |
| C 603e: ? |
| C 604e: 3.0 |
| C 75x (G3): 3.0 |
| C 7400,7410 (G4): 3.0 |
| C 7445,7455 (G4+): 2.5 |
| C 7447,7457 (G4+): 2.25 |
| C power4/ppc970: 2.5 |
| C power5: 2.5 |
| |
| C INPUT PARAMETERS |
| C rp r3 |
| C up r4 |
| C n r5 |
| C cnt r6 |
| |
| ASM_START() |
| PROLOGUE(mpn_rshift) |
| cmpwi cr0, r5, 12 C more than 12 limbs? |
| addi r7, r3, -4 C dst-4 |
| bgt L(BIG) C branch if more than 12 limbs |
| |
| mtctr r5 C copy size into CTR |
| subfic r8, r6, 32 |
| lwz r11, 0(r4) C load first s1 limb |
| slw r3, r11, r8 C compute function return value |
| bdz L(end1) |
| |
| L(oop): lwzu r10, 4(r4) |
| srw r9, r11, r6 |
| slw r12, r10, r8 |
| or r9, r9, r12 |
| stwu r9, 4(r7) |
| bdz L(end2) |
| lwzu r11, 4(r4) |
| srw r9, r10, r6 |
| slw r12, r11, r8 |
| or r9, r9, r12 |
| stwu r9, 4(r7) |
| bdnz L(oop) |
| |
| L(end1): |
| srw r0, r11, r6 |
| stw r0, 4(r7) |
| blr |
| L(end2): |
| srw r0, r10, r6 |
| stw r0, 4(r7) |
| blr |
| |
| L(BIG): |
| stmw r24, -32(r1) C save registers we are supposed to preserve |
| lwz r9, 0(r4) |
| subfic r8, r6, 32 |
| slw r3, r9, r8 C compute function return value |
| srw r0, r9, r6 |
| addi r5, r5, -1 |
| |
| andi. r10, r5, 3 C count for spill loop |
| beq L(e) |
| mtctr r10 |
| lwzu r28, 4(r4) |
| bdz L(xe0) |
| |
| L(loop0): |
| srw r12, r28, r6 |
| slw r24, r28, r8 |
| lwzu r28, 4(r4) |
| or r24, r0, r24 |
| stwu r24, 4(r7) |
| mr r0, r12 |
| bdnz L(loop0) C taken at most once! |
| |
| L(xe0): srw r12, r28, r6 |
| slw r24, r28, r8 |
| or r24, r0, r24 |
| stwu r24, 4(r7) |
| mr r0, r12 |
| |
| L(e): srwi r5, r5, 2 C count for unrolled loop |
| addi r5, r5, -1 |
| mtctr r5 |
| lwz r28, 4(r4) |
| lwz r29, 8(r4) |
| lwz r30, 12(r4) |
| lwzu r31, 16(r4) |
| |
| L(loopU): |
| srw r9, r28, r6 |
| slw r24, r28, r8 |
| lwz r28, 4(r4) |
| srw r10, r29, r6 |
| slw r25, r29, r8 |
| lwz r29, 8(r4) |
| srw r11, r30, r6 |
| slw r26, r30, r8 |
| lwz r30, 12(r4) |
| srw r12, r31, r6 |
| slw r27, r31, r8 |
| lwzu r31, 16(r4) |
| or r24, r0, r24 |
| stw r24, 4(r7) |
| or r25, r9, r25 |
| stw r25, 8(r7) |
| or r26, r10, r26 |
| stw r26, 12(r7) |
| or r27, r11, r27 |
| stwu r27, 16(r7) |
| mr r0, r12 |
| bdnz L(loopU) |
| |
| srw r9, r28, r6 |
| slw r24, r28, r8 |
| srw r10, r29, r6 |
| slw r25, r29, r8 |
| srw r11, r30, r6 |
| slw r26, r30, r8 |
| srw r12, r31, r6 |
| slw r27, r31, r8 |
| or r24, r0, r24 |
| stw r24, 4(r7) |
| or r25, r9, r25 |
| stw r25, 8(r7) |
| or r26, r10, r26 |
| stw r26, 12(r7) |
| or r27, r11, r27 |
| stw r27, 16(r7) |
| |
| stw r12, 20(r7) |
| lmw r24, -32(r1) C restore registers |
| blr |
| EPILOGUE(mpn_rshift) |
