286 lines
10 KiB
ArmAsm
286 lines
10 KiB
ArmAsm
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/*
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* (c) Copyright 1986 HEWLETT-PACKARD COMPANY
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*
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* To anyone who acknowledges that this file is provided "AS IS"
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* without any express or implied warranty:
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* permission to use, copy, modify, and distribute this file
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* for any purpose is hereby granted without fee, provided that
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* the above copyright notice and this notice appears in all
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* copies, and that the name of Hewlett-Packard Company not be
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* used in advertising or publicity pertaining to distribution
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* of the software without specific, written prior permission.
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* Hewlett-Packard Company makes no representations about the
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* suitability of this software for any purpose.
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*/
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/*
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A faster strcpy.
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by
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Jerry Huck (aligned case)
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Daryl Odnert (equal-alignment case)
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Edgar Circenis (non-aligned case)
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*/
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/*
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* strcpy(s1, s2)
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*
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* Copy string s2 to s1. s1 must be large enough.
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* return s1
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*/
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#include "DEFS.h"
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#define d_addr r26
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#define s_addr r25
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#define tmp6 r24
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#define tmp1 r19
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#define evenside r19
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#define tmp2 r20
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#define oddside r20
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#define tmp3 r21
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#define tmp4 r22
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#define tmp5 arg3
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#define save r1
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ENTRY(strcpy)
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/* Do some quick alignment checking on and fast path both word aligned */
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extru,<> s_addr,31,2,tmp6 /*Is source word aligned? */
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ldwm 4(0,s_addr),oddside /*Assume yes and guess that it
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is double-word aligned. */
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dep,= d_addr,29,2,tmp6 /*Is target word aligned? */
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b case_analysis
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copy d_addr,ret0
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/* Both are aligned. First source word already loaded assuming that
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source was oddword aligned. Fall through (therefore fastest) code
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shuffles the registers to join the main loop */
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bothaligned:
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bb,>= s_addr,29,twoatatime /*Branch if source was odd aligned*/
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uxor,nbz oddside,r0,save
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/* Even aligned source. save holds that operand.
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Do one iteration of the main copy loop juggling the registers to avoid
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one copy. */
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b,n nullfound
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ldwm 4(s_addr),oddside
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stwm save,4(d_addr)
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uxor,nbz oddside,r0,save
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b,n nullfound
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ldwm 4(s_addr),evenside
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stwm oddside,4(d_addr)
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uxor,nbz evenside,r0,save
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b,n nullfound
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ldwm 4(s_addr),oddside
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/* Main loop body. Entry expects evenside still to be stored, oddside
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just loaded. */
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loop:
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stwm evenside,4(d_addr)
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uxor,nbz oddside,r0,save
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/* mid loop entry */
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twoatatime:
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b,n nullfound
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ldwm 4(s_addr),evenside
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stwm oddside,4(d_addr)
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uxor,sbz evenside,r0,save
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b loop
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ldwm 4(s_addr),oddside
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/* fall through when null found in evenside. oddside actually loaded */
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nullfound: /* adjust d_addr and store final word */
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extru,<> save,7,8,r0 /* pick up leftmost byte */
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addib,tr,n 1,d_addr,store_final
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extru,<> save,15,8,r0
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addib,tr,n 2,d_addr,store_final
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extru,<> save,23,8,r0
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addib,tr 3,d_addr,store_final2
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bv 0(rp)
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stw save,0(d_addr)
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store_final:
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bv 0(rp)
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store_final2:
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stbys,e save,0(d_addr) /* delay slot */
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case_analysis:
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blr tmp6,r0
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nop
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/* NOTE: the delay slots for the non-aligned cases load a */
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/* shift quantity which is TGT-SRC into tmp3. */
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/* Note also, the case for both strings being word aligned */
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/* is already checked before the BLR is executed, so that */
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/* case can never occur. */
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/* TGT SRC */
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nop /* 00 00 can't happen */
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nop
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b neg_aligned_copy /* 00 01 */
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ldi -1,tmp3 /* load shift quantity. delay slot */
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b neg_aligned_copy /* 00 10 */
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ldi -2,tmp3 /* load shift quantity. delay slot */
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b neg_aligned_copy /* 00 11 */
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ldi -3,tmp3 /* load shift quantity. delay slot */
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b pos_aligned_copy0 /* 01 00 */
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ldi 1,tmp3 /* load shift quantity. delay slot */
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b equal_alignment_1 /* 01 01 */
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ldbs,ma 1(s_addr),tmp1
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b neg_aligned_copy /* 01 10 */
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ldi -1,tmp3 /* load shift quantity. delay slot */
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b neg_aligned_copy /* 01 11 */
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ldi -2,tmp3 /* load shift quantity. delay slot */
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b pos_aligned_copy0 /* 10 00 */
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ldi 2,tmp3 /* load shift quantity. delay slot */
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b pos_aligned_copy /* 10 01 */
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ldi 1,tmp3 /* load shift quantity. delay slot */
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b equal_alignment_2 /* 10 10 */
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ldhs,ma 2(s_addr),tmp1
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b neg_aligned_copy /* 10 11 */
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ldi -1,tmp3 /* load shift quantity. delay slot */
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b pos_aligned_copy0 /* 11 00 */
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ldi 3,tmp3 /* load shift quantity. delay slot */
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b pos_aligned_copy /* 11 01 */
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ldi 2,tmp3 /* load shift quantity. delay slot */
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b pos_aligned_copy /* 11 10 */
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ldi 1,tmp3 /* load shift quantity. delay slot */
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ldbs,ma 1(s_addr),tmp1 /* 11 11 */
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comiclr,<> r0,tmp1,r0
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bv 0(rp) /* return if 1st byte was null */
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stbs,ma tmp1,1(d_addr) /* store a byte to dst string */
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b bothaligned /* can now goto word_aligned */
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ldwm 4(s_addr),oddside /* load next word of source */
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equal_alignment_1:
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comiclr,<> r0,tmp1,r0 /* nullify next if tmp1 <> 0 */
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bv 0(rp) /* return if null byte found */
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stbs,ma tmp1,1(d_addr) /* store a byte to dst string */
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ldhs,ma 2(s_addr),tmp1 /* load next halfword */
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equal_alignment_2:
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extru,<> tmp1,23,8,tmp6 /* look at left byte of halfword */
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bv 0(rp) /* return if 1st byte was null */
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stbs,ma tmp6,1(d_addr)
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extru,<> tmp1,31,8,r0
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bv 0(rp) /* return if 2nd byte was null */
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stbs,ma tmp1,1(d_addr)
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b bothaligned
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ldwm 4(s_addr),oddside /* load next word */
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/* source and destination are not aligned, so we do it the hard way. */
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/* target alignment is greater than source alignment */
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pos_aligned_copy0:
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addi -4,s_addr,s_addr
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pos_aligned_copy:
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extru d_addr,31,2,tmp6 /* Extract low 2 bits of the dest addr */
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extru s_addr,31,2,tmp1 /* Extract low 2 bits of the src addr */
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dep r0,31,2,s_addr /* Compute word address of the source. */
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sh3add tmp3,r0,tmp4 /* compute shift amt */
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ldwm 4(0,s_addr),tmp2 /* get 1st source word */
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sh3add tmp1,r0,save /* setup mask shift amount */
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mtctl save,r11 /* set-up cr11 for mask */
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zvdepi -2,32,save /* create mask */
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or save,tmp2,tmp2 /* mask unused bytes in src */
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ldi -1,tmp1 /* load tmp1 with 0xffffffff */
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mtctl tmp4,r11 /* shift count -> shift count reg */
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vshd tmp1,tmp2,tmp3 /* position data ! */
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uxor,nbz tmp3,r0,save
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b,n first_null
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uxor,nbz tmp2,r0,save
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b nullfound1
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mtctl tmp4,r11 /* re-load shift cnt (delay slot) */
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b loop_entry
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ldwm 4(0,s_addr),tmp1 /* get next word. delay slot */
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neg_aligned_copy:
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extru d_addr,31,2,tmp6 /* Extract low 2 bits of the dest addr */
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extru s_addr,31,2,tmp2 /* Extract low 2 bits of the src addr */
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dep r0,31,2,s_addr /* Compute word address of the source. */
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sh3add tmp3,r0,tmp4 /* compute shift amt */
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ldwm 4(0,s_addr),tmp1 /* load first word from source. */
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/* check to see if next word can be read safely */
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sh3add tmp2,r0,save
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mtctl save,r11 /* shift count -> shift count reg */
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zvdepi -2,32,save
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or save, tmp1, tmp1
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uxor,nbz tmp1,r0,save /* any nulls in first word? */
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b first_null0
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mtctl tmp4,r11
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ldwm 4(0,s_addr),tmp2 /* load second word from source */
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combt,= tmp6,r0,chunk1 /* don't mask if whole word valid */
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vshd tmp1,tmp2,tmp3 /* position data ! */
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sh3add tmp6,r0,save /* setup r1 */
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mtctl save,r11 /* set-up cr11 for mask */
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zvdepi -2,32,save
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or save, tmp3, tmp3
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uxor,nbz tmp3,r0,save
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b,n first_null
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uxor,nbz tmp2,r0,save
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b nullfound1
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mtctl tmp4,r11 /* re-load shift cnt (delay slot) */
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b loop_entry
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ldwm 4(0,s_addr),tmp1 /* get next word. delay slot */
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chunk1:
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uxor,nbz tmp2,r0,save
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b nullfound0
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vshd tmp1,tmp2,tmp3
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did_mask:
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ldwm 4(0,s_addr),tmp1 /* get next word ! */
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loop_entry:
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stbys,b,m tmp3,4(0,d_addr) /* store ! */
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uxor,nbz tmp1, r0, save
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b nullfound2
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vshd tmp2,tmp1,tmp3 /* position data ! */
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ldwm 4(s_addr),tmp2
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stwm tmp3,4(d_addr)
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uxor,sbz tmp2,r0,save
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b did_mask
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nullfound0:
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vshd tmp1,tmp2,tmp3 /* delay slot */
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uxor,nbz tmp3,r0,save
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b,n nullfound
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nullfound1:
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stbys,b,m tmp3,4(0,d_addr)
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b nullfound
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vshd tmp2,r0,save /* delay slot */
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nullfound2:
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uxor,nbz tmp3,r0,save
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b,n nullfound
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stwm tmp3,4(d_addr)
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b nullfound
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/* notice that delay slot is in next routine */
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first_null0: /* null found in first word of non-aligned (wrt d_addr) */
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vshd tmp1,r0,save /* delay slot */
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combt,= tmp6,r0,check4
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extru save,7,8,tmp4
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first_null:
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addibt,= -1,tmp6,check3 /* check last 3 bytes of word */
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extru save,15,8,tmp4
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addibt,=,n -1,tmp6,check2 /* check last 2 bytes */
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bv 0(rp) /* null in last byte--store and exit */
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stbys,b save, 0(d_addr)
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check4:
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combt,= tmp4,r0,done
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stbs,ma tmp4,1(d_addr)
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extru,<> save,15,8,tmp4
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check3:
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combt,= tmp4,r0,done
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stbs,ma tmp4,1(d_addr)
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check2:
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extru,<> save,23,8,tmp4
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bv 0(rp)
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stbs,ma tmp4,1(d_addr)
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bv 0(rp)
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stbs r0,0(d_addr)
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done:
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EXIT(strcpy)
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