arch/.unmaintained/ppc-native/exec/getcc.s

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4 */
   5
   6 /*****************************************************************************
   7
   8     NAME
   9
  10         AROS_LH0(UWORD, GetCC,
  11
  12     LOCATION
  13         struct ExecBase *, SysBase, 88, Exec)
  14
  15     FUNCTION
  16         Read the contents of the sr in a easy and compatible way.
  17
  18     INPUTS
  19
  20     RESULT
  21         The contents of sr as a UWORD.
  22
  23     NOTES
  24
  25     EXAMPLE
  26
  27     BUGS
  28
  29     SEE ALSO
  30         SetSR()
  31
  32     INTERNALS
  33         I don't think this function will have any real use on PPC...
  34         This function maps PPC:
  35                 CA to C
  36                 OV to V
  37                 EQ to Z
  38                 ?? to N
  39                 CA to X
  40
  41     HISTORY
  42
  43 ******************************************************************************/
  44
  45         #include "machine.i"
  46
  47         .text
  48         .balign 4
  49         .globl  AROS_SLIB_ENTRY(GetCC,Exec)
  50         .type   AROS_SLIB_ENTRY(GetCC,Exec),@function
  51
  52 AROS_SLIB_ENTRY(GetCC,Exec):
  53         subr
  54         push    scr
  55         li      ret,0
  56         bne     _notequal       # Z=0
  57         ori     ret,ret,4       # Z=1
  58 _notequal:
  59         bge     _positive       # N=0
  60         ori     ret,ret,8       # N=1
  61 _positive:
  62         mfxer   scr
  63         rlwinm. scr,scr,1,0,0
  64         beq     _noovfl         # 0? so no Overflow
  65         ori     ret,ret,2       # V=1
  66 _noovfl:
  67         mfxer   scr
  68         rlwinm. scr,scr,2,0,0
  69         beq     _nocarry        # 0? so no Carry
  70         ori     ret,ret,17      # X=1 C=1
  71 _nocarry:
  72         pop     scr
  73         rts