sys/arch/hp700/stand/common/milli_tiny.S

   1 ;       $NetBSD: milli_tiny.S,v 1.2 2005/12/11 12:17:25 christos Exp $
   2
   3 ; Copyright (c) 2003 ITOH Yasufumi.
   4 ; All rights reserved.
   5 ;
   6 ; Redistribution and use in source and binary forms, with or without
   7 ; modification, are permitted provided that the following conditions
   8 ; are met:
   9 ; 1. Redistributions of source code must retain the above copyright
  10 ;    notice, this list of conditions and the following disclaimer.
  11 ; 2. Redistributions in binary forms are unlimited.
  12 ;
  13 ; THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS''
  14 ; AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  15 ; THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16 ; PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS
  17 ; BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  18 ; CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  19 ; SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  20 ; INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  21 ; CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  22 ; ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  23 ; THE POSSIBILITY OF SUCH DAMAGE.
  24
  25 ; millicode library, optimized for size
  26
  27         .level  1.0
  28         .code
  29         .align  4
  30
  31 ; $$divU        unsigned division, return quotient
  32 ;
  33 ; inputs:
  34 ;       %r26    dividend
  35 ;       %r25    divisor
  36 ;       %r31    return address
  37 ; outputs:
  38 ;       %r29    quotient
  39 ;       %r1, %r25, %r26 undefined
  40         .export         $$divU,millicode
  41 $$divU:
  42         .proc
  43         .callinfo       millicode,no_unwind
  44         .entry
  45         comb,<,n        %r25,0,bigdivisor_divU  ; special case (>=0x80000000)
  46         bl              sub_divU,%r29
  47         subt,=          %r0,%r25,%r1            ; trap divide by 0, negate
  48
  49         bv              %r0(%r31)               ; return millicode
  50         .exit
  51         addc            %r26,%r26,%r29          ; fix quotient
  52 bigdivisor_divU:
  53         comclr,<<       %r26,%r25,%r29          ; if dividend >= divisor
  54         ldi             1,%r29                  ;   quotient is 1
  55         bv,n            %r0(%r31)               ; return millicode
  56         .procend
  57
  58 ; Note this is not a normal subroutine
  59 ; r29: return address
  60 sub_divU:
  61         stwm            %r19,64(%sp)
  62         ldi             31,%r19
  63
  64         ds              %r0,%r1,%r0
  65         addc            %r26,%r26,%r26
  66         ds              %r0,%r25,%r1
  67 loop_sub_divU:                                  ; addc/ds 31 times
  68         addc            %r26,%r26,%r26
  69         addib,<>        -1,%r19,loop_sub_divU
  70         ds              %r1,%r25,%r1
  71
  72         bv              %r0(%r29)
  73         ldwm            -64(%sp),%r19
  74
  75 ; $$remU        unsigned division, return remainder
  76 ;
  77 ; inputs:
  78 ;       %r26    dividend
  79 ;       %r25    divisor
  80 ;       %r31    return address
  81 ; outputs:
  82 ;       %r29    remainder
  83 ;       %r1, %r25, %r26 undefined
  84         .export         $$remU,millicode
  85 $$remU:
  86         .proc
  87         .callinfo       millicode,no_unwind
  88         .entry
  89         comb,<,n        %r25,0,bigdivisor_remU  ; special case (>=0x80000000)
  90         bl              sub_divU,%r29
  91         subt,=          %r0,%r25,%r1            ; trap divide by 0, negate
  92
  93         comclr,>=       %r1,%r0,%r0
  94         addl            %r1,%r25,%r1            ; fix remainder
  95         bv              %r0(%r31)               ; return millicode
  96         .exit
  97         copy            %r1,%r29                ; the return value is remainder
  98 bigdivisor_remU:
  99         sub,>>=         %r26,%r25,%r29          ; if dividend < divisor
 100         copy            %r26,%r29               ;   the remainder is dividend
 101         bv,n            %r0(%r31)               ; return millicode
 102         .procend
 103
 104 ; $$mulU        unsigned multiplication
 105 ;
 106 ; inputs:
 107 ;       %r26    multiplicand
 108 ;       %r25    multiplier
 109 ;       %r31    return address
 110 ; outputs:
 111 ;       %r29    product
 112 ;       %r1, %r25, %r26 undefined
 113         .export         $$mulU,millicode
 114         .export         $$mulI,millicode
 115 $$mulU:
 116 $$mulI: ; XXX actually wrong (not signed) but works for small positive numbers
 117         .proc
 118         .callinfo       frame=0,no_calls,millicode
 119         .entry
 120         copy            %r0,%r29
 121         ldi             32,%r1                  ; loop counter
 122
 123         add,nuv         %r25,%r25,%r25          ; shift left, skip next if not C
 124 loop_mul:
 125         sh1add,tr       %r29,%r26,%r29          ; shift left and add, skip next
 126         sh1add          %r29,%r0,%r29           ; shift left only
 127         addib,<>,n      -1,%r1,loop_mul         ; check loop condition
 128         add,nuv         %r25,%r25,%r25          ; shift left, skip next if not C
 129         .exit
 130         bv,n            %r0(%r31)               ; return millicode
 131         .procend