/*******************************************************************************
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/*******************************************************************************
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*
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*
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* Copyright (c) 1993 Intel Corporation
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* Copyright (c) 1993 Intel Corporation
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*
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*
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* Intel hereby grants you permission to copy, modify, and distribute this
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* Intel hereby grants you permission to copy, modify, and distribute this
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* software and its documentation. Intel grants this permission provided
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* software and its documentation. Intel grants this permission provided
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* that the above copyright notice appears in all copies and that both the
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* that the above copyright notice appears in all copies and that both the
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* copyright notice and this permission notice appear in supporting
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* copyright notice and this permission notice appear in supporting
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* documentation. In addition, Intel grants this permission provided that
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* documentation. In addition, Intel grants this permission provided that
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* you prominently mark as "not part of the original" any modifications
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* you prominently mark as "not part of the original" any modifications
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* made to this software or documentation, and that the name of Intel
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* made to this software or documentation, and that the name of Intel
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* Corporation not be used in advertising or publicity pertaining to
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* Corporation not be used in advertising or publicity pertaining to
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* distribution of the software or the documentation without specific,
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* distribution of the software or the documentation without specific,
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* written prior permission.
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* written prior permission.
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*
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*
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* Intel Corporation provides this AS IS, WITHOUT ANY WARRANTY, EXPRESS OR
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* Intel Corporation provides this AS IS, WITHOUT ANY WARRANTY, EXPRESS OR
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* IMPLIED, INCLUDING, WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY
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* IMPLIED, INCLUDING, WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY
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* OR FITNESS FOR A PARTICULAR PURPOSE. Intel makes no guarantee or
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* OR FITNESS FOR A PARTICULAR PURPOSE. Intel makes no guarantee or
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* representations regarding the use of, or the results of the use of,
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* representations regarding the use of, or the results of the use of,
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* the software and documentation in terms of correctness, accuracy,
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* the software and documentation in terms of correctness, accuracy,
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* reliability, currentness, or otherwise; and you rely on the software,
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* reliability, currentness, or otherwise; and you rely on the software,
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* documentation and results solely at your own risk.
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* documentation and results solely at your own risk.
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*
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*
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* IN NO EVENT SHALL INTEL BE LIABLE FOR ANY LOSS OF USE, LOSS OF BUSINESS,
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* IN NO EVENT SHALL INTEL BE LIABLE FOR ANY LOSS OF USE, LOSS OF BUSINESS,
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* LOSS OF PROFITS, INDIRECT, INCIDENTAL, SPECIAL OR CONSEQUENTIAL DAMAGES
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* LOSS OF PROFITS, INDIRECT, INCIDENTAL, SPECIAL OR CONSEQUENTIAL DAMAGES
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* OF ANY KIND. IN NO EVENT SHALL INTEL'S TOTAL LIABILITY EXCEED THE SUM
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* OF ANY KIND. IN NO EVENT SHALL INTEL'S TOTAL LIABILITY EXCEED THE SUM
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* PAID TO INTEL FOR THE PRODUCT LICENSED HEREUNDER.
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* PAID TO INTEL FOR THE PRODUCT LICENSED HEREUNDER.
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*
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*
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******************************************************************************/
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******************************************************************************/
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.file "strcm_ca.s"
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.file "strcm_ca.s"
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#ifdef __PIC
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#ifdef __PIC
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.pic
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.pic
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#endif
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#endif
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#ifdef __PID
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#ifdef __PID
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.pid
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.pid
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#endif
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#endif
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/*
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/*
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* (c) copyright 1988,1993 Intel Corp., all rights reserved
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* (c) copyright 1988,1993 Intel Corp., all rights reserved
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*/
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*/
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/*
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/*
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procedure strcmp (optimized assembler version for the CA)
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procedure strcmp (optimized assembler version for the CA)
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result = strcmp (src1_addr, src2_addr)
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result = strcmp (src1_addr, src2_addr)
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compare the null terminated string pointed to by src1_addr to
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compare the null terminated string pointed to by src1_addr to
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the string space pointed to by src2_addr. Return 0 iff the strings
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the string space pointed to by src2_addr. Return 0 iff the strings
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are equal, -1 if src1_addr is lexicly less than src2_addr, and 1
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are equal, -1 if src1_addr is lexicly less than src2_addr, and 1
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if it is lexicly greater.
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if it is lexicly greater.
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Undefined behavior will occur if the end of either source string
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Undefined behavior will occur if the end of either source string
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(i.e. the terminating null byte) is in the last word of the program's
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(i.e. the terminating null byte) is in the last word of the program's
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allocated memory space. This is so because, in several cases, strcmp
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allocated memory space. This is so because, in several cases, strcmp
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will fetch ahead one word. Disallowing the fetch ahead would impose
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will fetch ahead one word. Disallowing the fetch ahead would impose
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a severe performance penalty.
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a severe performance penalty.
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This program handles five cases:
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This program handles five cases:
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1) both arguments start on a word boundary
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1) both arguments start on a word boundary
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2) neither are word aligned, but they are offset by the same amount
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2) neither are word aligned, but they are offset by the same amount
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3) source1 is word aligned, source2 is not
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3) source1 is word aligned, source2 is not
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4) source2 is word aligned, source1 is not
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4) source2 is word aligned, source1 is not
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5) neither is word aligned, and they are offset by differing amounts
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5) neither is word aligned, and they are offset by differing amounts
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At the time of this writing, only g0 thru g7 and g14 are available
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At the time of this writing, only g0 thru g7 and g14 are available
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for use in this leafproc; other registers would have to be saved and
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for use in this leafproc; other registers would have to be saved and
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restored. These nine registers are sufficient to implement the routine.
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restored. These nine registers are sufficient to implement the routine.
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The registers are used as follows:
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The registers are used as follows:
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g0 original src1 ptr; return result
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g0 original src1 ptr; return result
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g1 src2 ptr; 0xff -- byte extraction mask
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g1 src2 ptr; 0xff -- byte extraction mask
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g2 src1 word ptr
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g2 src1 word ptr
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g3 src2 word ptr
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g3 src2 word ptr
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Little endian:
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Little endian:
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g4 lsw of src1
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g4 lsw of src1
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g5 msw of src1
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g5 msw of src1
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g6 src2 word
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g6 src2 word
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g7 extracted src1
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g7 extracted src1
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Big endian:
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Big endian:
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g4 msw of src1
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g4 msw of src1
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g5 lsw of src1
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g5 lsw of src1
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g6 extracted src1
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g6 extracted src1
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g7 src2 word
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g7 src2 word
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g13 return address
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g13 return address
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g14 shift count
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g14 shift count
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*/
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*/
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#if __i960_BIG_ENDIAN__
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#if __i960_BIG_ENDIAN__
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#define MSW g4
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#define MSW g4
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#define LSW g5
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#define LSW g5
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#define SRC1 g6
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#define SRC1 g6
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#define SRC2 g7
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#define SRC2 g7
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#else
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#else
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#define LSW g4
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#define LSW g4
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#define MSW g5
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#define MSW g5
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#define SRC2 g6
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#define SRC2 g6
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#define SRC1 g7
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#define SRC1 g7
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#endif
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#endif
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.globl _strcmp
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.globl _strcmp
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.globl __strcmp
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.globl __strcmp
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.leafproc _strcmp, __strcmp
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.leafproc _strcmp, __strcmp
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.align 2
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.align 2
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_strcmp:
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_strcmp:
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#ifndef __PIC
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#ifndef __PIC
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lda Lrett,g14
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lda Lrett,g14
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#else
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#else
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lda Lrett-(.+8)(ip),g14
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lda Lrett-(.+8)(ip),g14
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#endif
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#endif
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__strcmp:
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__strcmp:
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Lrestart:
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Lrestart:
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notand g0,3,g2 # extract word addr of start of src1
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notand g0,3,g2 # extract word addr of start of src1
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lda (g14),g13 # preserve return address
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lda (g14),g13 # preserve return address
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#if __i960_BIG_ENDIAN__
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#if __i960_BIG_ENDIAN__
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cmpo g0,g2 # check alignment of src1
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cmpo g0,g2 # check alignment of src1
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#endif
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#endif
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ld (g2),LSW # fetch word with at least first byte of src1
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ld (g2),LSW # fetch word with at least first byte of src1
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notand g1,3,g3 # extract word addr of start of src2
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notand g1,3,g3 # extract word addr of start of src2
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ld 4(g2),MSW # fetch second word of src1
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ld 4(g2),MSW # fetch second word of src1
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#if __i960_BIG_ENDIAN__
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#if __i960_BIG_ENDIAN__
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bne Lsrc1_unaligned # branch if src1 is unaligned
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bne Lsrc1_unaligned # branch if src1 is unaligned
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cmpo g3,g1 # check alignment of src2
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cmpo g3,g1 # check alignment of src2
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ld (g3),SRC2 # fetch word with at least first byte of src2
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ld (g3),SRC2 # fetch word with at least first byte of src2
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mov LSW,SRC1 # extract word of src1
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mov LSW,SRC1 # extract word of src1
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lda 8(g2),g2 # advance src1 word addr
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lda 8(g2),g2 # advance src1 word addr
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bne.f Lsrc2_unaligned # branch if src2 is NOT word aligned
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bne.f Lsrc2_unaligned # branch if src2 is NOT word aligned
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/* src2 is word aligned */
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/* src2 is word aligned */
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Lwloop2: # word comparing loop
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Lwloop2: # word comparing loop
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cmpo SRC2,SRC1 # compare src1 and src2 words
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cmpo SRC2,SRC1 # compare src1 and src2 words
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lda 0xff000000,g1 # byte extraction mask
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lda 0xff000000,g1 # byte extraction mask
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mov MSW,LSW # move msw of src1 to lsw
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mov MSW,LSW # move msw of src1 to lsw
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ld (g2),MSW # pre-fetch next msw of src1
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ld (g2),MSW # pre-fetch next msw of src1
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addo 4,g2,g2 # post-increment src1 addr
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addo 4,g2,g2 # post-increment src1 addr
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lda 4(g3),g3 # pre-increment src2 addr
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lda 4(g3),g3 # pre-increment src2 addr
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bne.f Lcloop # branch if src1 and src2 unequal
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bne.f Lcloop # branch if src1 and src2 unequal
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scanbyte 0,SRC1 # check for null byte in src1 word
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scanbyte 0,SRC1 # check for null byte in src1 word
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ld (g3),SRC2 # pre-fetch next word of src2
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ld (g3),SRC2 # pre-fetch next word of src2
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mov LSW,SRC1 # extract word of src1
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mov LSW,SRC1 # extract word of src1
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lda 0,g0 # prepare to return zero, indicating equality
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lda 0,g0 # prepare to return zero, indicating equality
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bno.t Lwloop2 # branch if null byte not encountered
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bno.t Lwloop2 # branch if null byte not encountered
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/* words were equal and contained null byte */
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/* words were equal and contained null byte */
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mov 0,g14 # conform to register conventions
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mov 0,g14 # conform to register conventions
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bx (g13) # return
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bx (g13) # return
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Lsrc1_unaligned:
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Lsrc1_unaligned:
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#endif
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#endif
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cmpo g3,g1 # check alignment of src2
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cmpo g3,g1 # check alignment of src2
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ld (g3),SRC2 # fetch word with at least first byte of src2
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ld (g3),SRC2 # fetch word with at least first byte of src2
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shlo 3,g0,g14 # compute shift count for src1
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shlo 3,g0,g14 # compute shift count for src1
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#if __i960_BIG_ENDIAN__
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#if __i960_BIG_ENDIAN__
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subo g14,0,g14 # 32 - shift count for big endian.
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subo g14,0,g14 # 32 - shift count for big endian.
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#endif
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#endif
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eshro g14,g4,SRC1 # extract word of src1
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eshro g14,g4,SRC1 # extract word of src1
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lda 8(g2),g2 # advance src1 word addr
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lda 8(g2),g2 # advance src1 word addr
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bne.f Lsrc2_unaligned # branch if src2 is NOT word aligned
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bne.f Lsrc2_unaligned # branch if src2 is NOT word aligned
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/* at least src2 is word aligned */
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/* at least src2 is word aligned */
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Lwloop: # word comparing loop
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Lwloop: # word comparing loop
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cmpo SRC2,SRC1 # compare src1 and src2 words
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cmpo SRC2,SRC1 # compare src1 and src2 words
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#if __i960_BIG_ENDIAN__
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#if __i960_BIG_ENDIAN__
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lda 0xff000000,g1 # byte extraction mask
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lda 0xff000000,g1 # byte extraction mask
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#else
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#else
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lda 0xff,g1 # byte extraction mask
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lda 0xff,g1 # byte extraction mask
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#endif
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#endif
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mov MSW,LSW # move msw of src1 to lsw
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mov MSW,LSW # move msw of src1 to lsw
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ld (g2),MSW # pre-fetch next msw of src1
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ld (g2),MSW # pre-fetch next msw of src1
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addo 4,g2,g2 # post-increment src1 addr
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addo 4,g2,g2 # post-increment src1 addr
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lda 4(g3),g3 # pre-increment src2 addr
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lda 4(g3),g3 # pre-increment src2 addr
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bne.f Lcloop # branch if src1 and src2 unequal
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bne.f Lcloop # branch if src1 and src2 unequal
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scanbyte 0,SRC1 # check for null byte in src1 word
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scanbyte 0,SRC1 # check for null byte in src1 word
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ld (g3),SRC2 # pre-fetch next word of src2
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ld (g3),SRC2 # pre-fetch next word of src2
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eshro g14,g4,SRC1 # extract word of src1
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eshro g14,g4,SRC1 # extract word of src1
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lda 0,g0 # prepare to return zero, indicating equality
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lda 0,g0 # prepare to return zero, indicating equality
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bno.t Lwloop # branch if null byte not encountered
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bno.t Lwloop # branch if null byte not encountered
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/* words were equal and contained null byte */
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/* words were equal and contained null byte */
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mov 0,g14 # conform to register conventions
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mov 0,g14 # conform to register conventions
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bx (g13) # return
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bx (g13) # return
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Lcloop_setup: # setup for coming from Lsrc2_unaligned
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Lcloop_setup: # setup for coming from Lsrc2_unaligned
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mov LSW,SRC1 # restore extracted src1 word
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mov LSW,SRC1 # restore extracted src1 word
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#if __i960_BIG_ENDIAN__
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#if __i960_BIG_ENDIAN__
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lda 0xff000000,g1 # byte extraction mask
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lda 0xff000000,g1 # byte extraction mask
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#else
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#else
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lda 0xff,g1 # byte extraction mask
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lda 0xff,g1 # byte extraction mask
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#endif
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#endif
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Lcloop: # character comparing loop
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Lcloop: # character comparing loop
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and SRC2,g1,g3 # extract next char of src2
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and SRC2,g1,g3 # extract next char of src2
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and SRC1,g1,g0 # extract next char of src1
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and SRC1,g1,g0 # extract next char of src1
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cmpobne.f g0,g3,.diff # check for equality
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cmpobne.f g0,g3,.diff # check for equality
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cmpo 0,g0 # check for null byte
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cmpo 0,g0 # check for null byte
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#if __i960_BIG_ENDIAN__
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#if __i960_BIG_ENDIAN__
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shro 8,g1,g1 # shift mask for next byte
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shro 8,g1,g1 # shift mask for next byte
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#else
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#else
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shlo 8,g1,g1 # shift mask for next byte
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shlo 8,g1,g1 # shift mask for next byte
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#endif
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#endif
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bne.t Lcloop # branch if null not reached
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bne.t Lcloop # branch if null not reached
|
|
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/* words are equal up thru null byte */
|
/* words are equal up thru null byte */
|
|
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mov 0,g14
|
mov 0,g14
|
bx (g13) # g0 = 0 (src1 == src2)
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bx (g13) # g0 = 0 (src1 == src2)
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Lrett:
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Lrett:
|
ret
|
ret
|
|
|
.diff:
|
.diff:
|
mov 0,g14
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mov 0,g14
|
bl Lless_than_exit
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bl Lless_than_exit
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Lgreater_than_exit:
|
Lgreater_than_exit:
|
mov 1,g0
|
mov 1,g0
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bx (g13) # g0 = 1 (src1 > src2)
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bx (g13) # g0 = 1 (src1 > src2)
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Lless_than_exit:
|
Lless_than_exit:
|
subi 1,0,g0
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subi 1,0,g0
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bx (g13) # g0 = -1 (src1 < src2)
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bx (g13) # g0 = -1 (src1 < src2)
|
|
|
Lsrc2_unaligned:
|
Lsrc2_unaligned:
|
mov SRC1,LSW # retain src1 extracted word
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mov SRC1,LSW # retain src1 extracted word
|
ld 4(g3),SRC1 # fetch second word of src2
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ld 4(g3),SRC1 # fetch second word of src2
|
shlo 3,g1,MSW # compute shift count for src2
|
shlo 3,g1,MSW # compute shift count for src2
|
#if __i960_BIG_ENDIAN__
|
#if __i960_BIG_ENDIAN__
|
subo MSW,0,MSW # 32 - shift count for big endian.
|
subo MSW,0,MSW # 32 - shift count for big endian.
|
#endif
|
#endif
|
eshro MSW,g6,SRC2 # extract word of src2
|
eshro MSW,g6,SRC2 # extract word of src2
|
cmpo LSW,SRC2 # compare src1 and src2 words
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cmpo LSW,SRC2 # compare src1 and src2 words
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notor g1,3,MSW # first step in computing new src1 ptr
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notor g1,3,MSW # first step in computing new src1 ptr
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lda 4(g3),g1 # set new src2 ptr
|
lda 4(g3),g1 # set new src2 ptr
|
bne.f Lcloop_setup # first four bytes differ
|
bne.f Lcloop_setup # first four bytes differ
|
scanbyte 0,LSW # check for null byte
|
scanbyte 0,LSW # check for null byte
|
lda (g13),g14 # prepare return pointer for Lrestart
|
lda (g13),g14 # prepare return pointer for Lrestart
|
subo MSW,g0,g0 # second (final) step in computing new src1 ptr
|
subo MSW,g0,g0 # second (final) step in computing new src1 ptr
|
bno.t Lrestart # if null byte not encountered, continue
|
bno.t Lrestart # if null byte not encountered, continue
|
/* with both string fetches shifted such that */
|
/* with both string fetches shifted such that */
|
/* src2 is now word aligned. */
|
/* src2 is now word aligned. */
|
mov 0,g14 # conform to register conventions.
|
mov 0,g14 # conform to register conventions.
|
lda 0,g0 # return indicator of equality.
|
lda 0,g0 # return indicator of equality.
|
bx (g13)
|
bx (g13)
|
|
|
