BSD 4_4 release

[unix-history] / usr / src / lib / libc / vax / gen / udiv.s

diff --git a/usr/src/lib/libc/vax/gen/udiv.s b/usr/src/lib/libc/vax/gen/udiv.s
index c7d1daf..7f3f0a4 100644 (file)
--- a/usr/src/lib/libc/vax/gen/udiv.s
+++ b/usr/src/lib/libc/vax/gen/udiv.s
@@ -1,77 +1,95 @@
-#ifdef LIBC_SCCS
-       .asciz  "@(#)udiv.s     5.2 (Berkeley) 3/9/86"
-#endif LIBC_SCCS
-
-/*
- * udiv - unsigned division for vax-11
+/*-
+ * Copyright (c) 1991, 1993
+ *     The Regents of the University of California.  All rights reserved.

  *
  *

- * arguments: dividend, divisor.
- * result: quotient.
- * uses r0-r2
+ * This code is derived from software contributed to Berkeley by
+ * Donn Seeley at UUNET Technologies, Inc.

  *
  *

- * If 1 < divisor <= 2147483647, zero-extend the dividend
- * to 64 bits and let ediv do the work.  If the divisor is 1,
- * ediv will overflow if bit 31 of the dividend is on, so
- * just return the dividend unchanged.  If the divisor is 0,
- * do the ediv also, so it will generate the proper exception.
- * All other values of the divisor have bit 31 on: in this case
- * the quotient must be 0 if divisor > dividend, and 1 otherwise,
- * provided that the comparison is made as unsigned.
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *     This product includes software developed by the University of
+ *     California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.

  */
 
  */
 

-#include "DEFS.h"
-
-ASENTRY(udiv, 0)
-       movl    4(ap),r0        /* dividend */
-       movl    8(ap),r2        /* divisor */
-       jeql    1f              /* if divisor=0, force exception */
-       cmpl    r2,$1           /* if divisor <= 1 (signed), */
-       jleq    2f              /*  no division is necessary */
-1:
-       clrl    r1              /* zero-extend the dividend */
-       ediv    r2,r0,r0,r2     /* divide.  q->r0, r->r2 (discarded) */
-       ret
-2:     
-       jeql    1f              /* if divisor=1, return dividend */
-       cmpl    r0,r2           /* unsigned comparison between */
-       jgequ   2f              /*  dividend and divisor */
-       clrl    r0              /* dividend < divisor, return 0 */
-       ret
-2:     
-       movl    $1,r0           /* dividend >= divisor, return 1 */
-1:     
-       ret
+#if defined(LIBC_SCCS) && !defined(lint)
+       .asciz "@(#)udiv.s      8.1 (Berkeley) 6/4/93"
+#endif /* LIBC_SCCS and not lint */

 
 /*
 
 /*

- * audiv - unsigned division for vax-11
- *
- * arguments: *dividend, divisor.
- * result: quotient in r0 and *dividend.
- * uses r0-r2
+ * Unsigned division, PCC flavor.
+ * udiv() takes an ordinary dividend/divisor pair;
+ * audiv() takes a pointer to a dividend and an ordinary divisor.

  */
 
 #include "DEFS.h"
 
  */
 
 #include "DEFS.h"
 

-ASENTRY(audiv, 0)
-       movl    *4(ap),r0       /* dividend */
-       movl    8(ap),r2        /* divisor */
-       jeql    1f              /* if divisor=0, force exception */
-       cmpl    r2,$1           /* if divisor <= 1 (signed), */
-       jleq    2f              /*  no division is necessary */
-1:
-       clrl    r1              /* zero-extend the dividend */
-       ediv    r2,r0,r0,r2     /* divide.  q->r0, r->r2 (discarded) */
-       movl    r0,*4(ap)       /* save result */
+#define        DIVIDEND        4(ap)
+#define        DIVISOR         8(ap)
+
+ASENTRY(udiv,0)
+       movl    DIVISOR,r2
+       jlss    Leasy           # big divisor: settle by comparison
+       movl    DIVIDEND,r0
+       jlss    Lhard           # big dividend: extended division
+       divl2   r2,r0           # small divisor and dividend: signed division
+       ret
+Lhard:
+       clrl    r1
+       ediv    r2,r0,r0,r1
+       ret
+Leasy:
+       cmpl    DIVIDEND,r2
+       jgequ   Lone            # if dividend is as big or bigger, return 1
+       clrl    r0              # else return 0
+       ret
+Lone:
+       movl    $1,r0
+       ret
+
+ASENTRY(audiv,0)
+       movl    DIVIDEND,r3
+       movl    DIVISOR,r2
+       jlss    La_easy         # big divisor: settle by comparison
+       movl    (r3),r0
+       jlss    La_hard         # big dividend: extended division
+       divl2   r2,r0           # small divisor and dividend: signed division
+       movl    r0,(r3)         # leave the value of the assignment in r0
+       ret
+La_hard:
+       clrl    r1
+       ediv    r2,r0,r0,r1
+       movl    r0,(r3)

        ret
        ret

-2:
-       jeql    1f              /* if divisor=1, return dividend */
-       cmpl    r0,r2           /* unsigned comparison between */
-       jgequ   2f              /*  dividend and divisor */
-       clrl    r0              /* dividend < divisor, return 0 */
-       clrl    *4(ap)          /* save result */
+La_easy:
+       cmpl    (r3),r2
+       jgequ   La_one          # if dividend is as big or bigger, return 1
+       clrl    r0              # else return 0
+       clrl    (r3)

        ret
        ret

-2:
-       movl    $1,r0           /* dividend >= divisor, return 1 */
-1:
-       movl    r0,*4(ap)       /* save result */
+La_one:
+       movl    $1,r0
+       movl    r0,(r3)

        ret
        ret