; Copyright (C) 2011-2019 Free Software Foundation, Inc. ; Contributed by Red Hat. ; ; This file is free software; you can redistribute it and/or modify it ; under the terms of the GNU General Public License as published by the ; Free Software Foundation; either version 3, or (at your option) any ; later version. ; ; This file is distributed in the hope that it will be useful, but ; WITHOUT ANY WARRANTY; without even the implied warranty of ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU ; General Public License for more details. ; ; Under Section 7 of GPL version 3, you are granted additional ; permissions described in the GCC Runtime Library Exception, version ; 3.1, as published by the Free Software Foundation. ; ; You should have received a copy of the GNU General Public License and ; a copy of the GCC Runtime Library Exception along with this program; ; see the files COPYING3 and COPYING.RUNTIME respectively. If not, see ; . #include "vregs.h" START_FUNC ___lshrsi3 ;; input: ;; ;; [zero] ;; [count] <= $sp+8 ;; [in MSB] ;; [in] ;; [in] ;; [in LSB] <- $sp+4 ;; output: ;; ;; [r8..r11] result ;; registers: ;; ;; AX - temp for shift/rotate ;; B - count mov a, [sp+8] ; A now contains the count cmp a, #0x20 bc $.Lcount_is_normal ;; count is out of bounds, just return zero. movw r8, #0 movw r10, #0 ret .Lcount_is_normal: cmp0 a bnz $.Lcount_is_nonzero ;; count is zero, just copy IN to OUT movw ax, [sp+4] movw r8, ax movw ax, [sp+6] movw r10, ax ret .Lcount_is_nonzero: mov b, a ; B now contains the count also bf a.4, $.Lcount_lt_16 ;; count >= 16, shift 16 at a time. movw r10, #0 movw ax, [sp+6] movw r8, ax mov a, b and a, #0x0f sknz ret mov b, a ; B now contains the remaining count inc b br $.Lloop_top .Lcount_lt_16: ;; count is nonzero. Do one movw ax, [sp+6] shrw ax,1 movw r10, ax mov a, [sp+5] rorc a,1 mov r9, a mov a, [sp+4] rorc a,1 mov r8, a ;; we did one shift above; do as many more as we need now. .Lloop_top: dec b sknz ret movw ax, r10 shrw ax,1 movw r10, ax mov a, r9 rorc a,1 mov r9, a mov a, r8 rorc a,1 mov r8, a br $.Lloop_top END_FUNC ___lshrsi3