4.3BSD - /usr/src/lib/libc/vax/gen/urem.s

   1: #ifdef LIBC_SCCS
   2:         .asciz  "@(#)urem.s	5.2 (Berkeley) 3/9/86"
   3: #endif LIBC_SCCS
   4: 
   5: /*
   6:  * urem - unsigned remainder for vax-11
   7:  *
   8:  * arguments: dividend, divisor
   9:  * result: remainder
  10:  * uses r0-r2
  11:  *
  12:  * if 1 < divisor <= 2147483647, zero-extend the dividend
  13:  * to 64 bits and let ediv do the work.  If the divisor is 1,
  14:  * ediv will overflow if bit 31 of the dividend is on, so
  15:  * just return 0.  If the divisor is 0, do the ediv also,
  16:  * so it will generate the proper exception.  All other values
  17:  * of the divisor have bit 31 on: in this case the remainder
  18:  * must be the dividend if divisor > dividend, and the dividend
  19:  * minus the divisor otherwise.  The comparison must be unsigned.
  20:  */
  21: #include "DEFS.h"
  22: 
  23: ASENTRY(urem, 0)
  24:         movl    4(ap),r0        /* dividend */
  25:         movl    8(ap),r2        /* divisor */
  26:         jeql    1f              /* if divisor=0, force exception */
  27:         cmpl    r2,$1           /* if divisor <= 1 (signed), */
  28:         jleq    2f              /*  no division is necessary */
  29: 1:
  30:         clrl    r1              /* zero-extend the dividend */
  31:         ediv    r2,r0,r2,r0     /* divide.  q->r2 (discarded), r->r0 */
  32:         ret
  33: 2:
  34:         jneq    1f              /* if divisor=1, return 0 */
  35:         clrl    r0              /*  (because doing the divide will overflow */
  36:         ret                     /*  if the dividend has its high bit on) */
  37: 1:
  38:         cmpl    r0,r2           /* if dividend < divisor (unsigned) */
  39:         jlssu   1f              /*  remainder is dividend */
  40:         subl2   r2,r0           /*  else remainder is dividend - divisor */
  41: 1:
  42:         ret
  43: 
  44: /*
  45:  * aurem - unsigned remainder for vax-11
  46:  *
  47:  * arguments: *dividend, divisor
  48:  * result: remainder in r0 and *dividend
  49:  * uses r0-r2
  50:  */
  51: #include "DEFS.h"
  52: 
  53: ASENTRY(aurem, 0)
  54:         movl    *4(ap),r0       /* dividend */
  55:         movl    8(ap),r2        /* divisor */
  56:         jeql    1f              /* if divisor=0, force exception */
  57:         cmpl    r2,$1           /* if divisor <= 1 (signed), */
  58:         jleq    2f              /*  no division is necessary */
  59: 1:
  60:         clrl    r1              /* zero-extend the dividend */
  61:         ediv    r2,r0,r2,r0     /* divide.  q->r2 (discarded), r->r0 */
  62:         movl    r0,*4(ap)       /* save result */
  63:         ret
  64: 2:
  65:         jneq    1f              /* if divisor=1, return 0 */
  66:         clrl    r0              /*  (because doing the divide will overflow */
  67:         clrl    *4(ap)          /*  if the dividend has its high bit on) */
  68:         ret
  69: 1:
  70:         cmpl    r0,r2           /* if dividend < divisor (unsigned) */
  71:         jlssu   1f              /*  remainder is dividend */
  72:         subl2   r2,r0           /*  else remainder is dividend - divisor */
  73: 1:
  74:         movl    r0,*4(ap)       /* save result */
  75:         ret

Defined functions