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/*
 *  (c) Copyright 1986 HEWLETT-PACKARD COMPANY
 *
 *  To anyone who acknowledges that this file is provided "AS IS"
 *  without any express or implied warranty:
 *      permission to use, copy, modify, and distribute this file
 *  for any purpose is hereby granted without fee, provided that
 *  the above copyright notice and this notice appears in all
 *  copies, and that the name of Hewlett-Packard Company not be
 *  used in advertising or publicity pertaining to distribution
 *  of the software without specific, written prior permission.
 *  Hewlett-Packard Company makes no representations about the
 *  suitability of this software for any purpose.
 */

/* HPUX_ID:     @(#) $Revision: 1.1.1.2 $       */
/*
 * strcat(s1, s2)
 *
 * Concatenate s2 on the end of s1.  S1's space must be large enough.
 * Return s1.
 */
#include "DEFS.h"

#define d_addr  r26
#define s_addr  r25
#define tmp6    r24
#define tmp1    r19
#define tmp2    r20
#define tmp3    r21
#define tmp4    r22
#define tmp5    arg3
#define save    r1


ENTRY(strcat)

        comb,=          r0,s_addr,done  /* quit if s2=NULL */
        copy      d_addr,ret0          /* The return value is the value of d_addr. DELAY SLOT*/

/* First look for end of s1 (d_addr) */

        extru       d_addr,31,2,tmp1   /* Extract the low two bits of the dest address. */
        combt,=         tmp1,r0,dont_mask
        dep             0,31,2,d_addr   /*set word alignment */
        ldwm            4(d_addr),tmp2
        sh3add          tmp1,r0,save    /* build mask based on tmp1 */
        mtctl           save,11
        zvdepi          -2,32,save
        or              save,tmp2,tmp2
        uxor,nbz        tmp2,r0,save
search:
        b,n             found_end       /* nullified under uxor conditions above and below */
dont_mask:
        ldwm            4(d_addr),tmp2
        comib,tr        r0,r0,search
        uxor,nbz        tmp2,r0,save

found_end:                              /* at this point d_addr points to word */
        extru,<>        save,7,8,r0     /* following word with null */
        addib,tr,n      -4,d_addr,begin_copy    /*set d_addr to end of s1 */
        extru,<>        save,15,8,r0
        addib,tr,n      -3,d_addr,begin_copy
        extru,<>        save,23,8,r0
        addi            -1,d_addr,d_addr
        addi            -1,d_addr,d_addr


begin_copy:

        extru       s_addr,31,2,tmp1   /* Extract the low two bits of the source address. */
        extru       d_addr,31,2,tmp6   /* Extract the low two bits of the destination address. */
        sub,=       tmp6,tmp1,tmp3     /* Compute the shift quantity and don't branch if tmp6=tmp1. */
        b           not_aligned        /* Not_aligned says that shifts Will be needed. */
        dep         0,31,2,s_addr      /* Compute the word address of the source.  DELAY SLOT. */
/* aligned */

        combt,=         tmp6,r0,skip_mask
        ldwm            4(0,s_addr),tmp1   /* tmp1 = *s_addr   s_addr += 4 (DELAY SLOT) */
        sh3add          tmp6,r0,save
        mtctl           save,r11
        zvdepi          -2,32,save
        or              save,tmp1,tmp1
        uxor,nbz        tmp1,r0,save
        b,n             first_null      /* special case: null in first word */
        b,n             skip_mask2

chunks:
        b,n             null_found      /* delay slot for uxor below */

skip_mask2:
        stbys,b,m       tmp1,4(d_addr)
        ldwm            4(s_addr),tmp1
skip_mask:
        comib,tr        0,0,chunks
        uxor,nbz        tmp1,r0,save

/* Begin non_aligned code.  */

not_aligned:
        sh3add,>=       tmp3,r0,tmp4        /* compute the shift amt.and skip load if tmp6 > tmp1. */
        ldwm            4(0,s_addr),tmp1    /* load up the first word from the source. tmp1 = *s_addr++ */
        ldwm            4(0,s_addr),tmp2    /* get either first or second word from source.  */
        combt,=         tmp6,r0,chunk2      /* don't mask if whole word is valid */
        mtctl           tmp4,11             /* load the shift count into cr11 = shift count register. */
        vshd            tmp1,tmp2,tmp3      /* position data !  (delay slot) */
        sh3add          tmp6,r0,save        /* setup r1 */
        mtctl           save,r11            /* set-up cr11 for mask */
        zvdepi          -2,32,save
        or              save, tmp3, tmp3
        uxor,nbz        tmp3,r0,save
        b,n             first_null2
        b               did_mask
        mtctl           tmp4,11            /* re-load the shift count into cr11 */

chunk2:
        vshd            tmp1,tmp2,tmp3
        uxor,nbz        tmp3, r0, save
        b,n             null_found
did_mask:
        stbys,b,m       tmp3,4(0,d_addr)    /* store !  */

        ldwm            4(0,s_addr),tmp1    /* get next word !  */
        vshd            tmp2,tmp1,tmp3      /* position data !  */
        uxor,nbz        tmp3, r0, save
        b,n             null_found
        stwm            tmp3,4(d_addr)
        comib,tr        0,0,chunk2
        ldwm            4(s_addr),tmp2


null_found:                             /* adjust d_addr and store final word */

        extru,<>        save,7,8,r0
        addib,tr,n      1,d_addr,store_final
        extru,<>        save,15,8,r0
        addib,tr,n      2,d_addr,store_final
        extru,<>        save,23,8,r0
        addib,tr        3,d_addr,store_final2
        bv              0(r2)
        stw             save,0(d_addr)

store_final:
        bv              0(r2)
store_final2:
        stbys,e         save,0(d_addr)  /* delay slot */

first_null:                     /* null found in first word of aligned (wrt d_addr) */
        addi            -4,s_addr,s_addr
        ldbx            tmp6(s_addr),tmp4
        add             tmp6,s_addr,s_addr
        comib,=         0,tmp4,done
        stbs,ma         tmp4,1(d_addr)
        ldbs            1(s_addr),tmp4
        comib,=         0,tmp4,done
        stbs,ma         tmp4,1(d_addr)
        bv              0(r2)           /* done */
        stbs            0,0(d_addr)

first_null2:    /* null found in first word of non-aligned (wrt d_addr) */
        addibt,=        -1,tmp6,check3  /* check last 3 bytes of word */
        extru           save,15,8,tmp4
        addibt,=,n      -1,tmp6,check2  /* check last 2 bytes */
        bv              0(r2)
        stbys,b         save, 0(d_addr)

check3:
        combt,=         tmp4,r0,done
        stbs,ma         tmp4,1(d_addr)
check2:
        extru,<>        save,23,8,tmp4
        bv              0(r2)
        stbs,ma         tmp4,1(d_addr)
        bv              0(r2)
        stbs            r0,0(d_addr)

done:
EXIT(strcat)