1/* 2 * This code was copied from arch/powerpc/kernel/misc_32.S in the Linux 3 * kernel sources (commit 85e2efbb1db9a18d218006706d6e4fbeb0216213, also 4 * known as 2.6.38-rc5). The source file copyrights are as follows: 5 * 6 * (C) Copyright 1995-1996 Gary Thomas (gdt@linuxppc.org) 7 * 8 * Largely rewritten by Cort Dougan (cort@cs.nmt.edu) 9 * and Paul Mackerras. 10 * 11 * This program is free software; you can redistribute it and/or 12 * modify it under the terms of the GNU General Public License as 13 * published by the Free Software Foundation; either version 2 of 14 * the License, or (at your option) any later version. 15 */ 16 17#include <ppc_asm.tmpl> 18#include <ppc_defs.h> 19#include <config.h> 20 21/* 22 * Extended precision shifts. 23 * 24 * Updated to be valid for shift counts from 0 to 63 inclusive. 25 * -- Gabriel 26 * 27 * R3/R4 has 64 bit value 28 * R5 has shift count 29 * result in R3/R4 30 * 31 * ashrdi3: arithmetic right shift (sign propagation) 32 * lshrdi3: logical right shift 33 * ashldi3: left shift 34 */ 35 .globl __lshrdi3 36__lshrdi3: 37 subfic r6,r5,32 38 srw r4,r4,r5 # LSW = count > 31 ? 0 : LSW >> count 39 addi r7,r5,32 # could be xori, or addi with -32 40 slw r6,r3,r6 # t1 = count > 31 ? 0 : MSW << (32-count) 41 srw r7,r3,r7 # t2 = count < 32 ? 0 : MSW >> (count-32) 42 or r4,r4,r6 # LSW |= t1 43 srw r3,r3,r5 # MSW = MSW >> count 44 or r4,r4,r7 # LSW |= t2 45 blr 46