Games/Quake/sys_dosa.s

   1 //
   2 // sys_dosa.s
   3 // x86 assembly-language DOS-dependent routines.
   4
   5 #include "asm_i386.h"
   6 #include "quakeasm.h"
   7
   8
   9         .data
  10
  11         .align  4
  12 fpenv:
  13         .long   0, 0, 0, 0, 0, 0, 0, 0
  14
  15         .text
  16
  17 .globl C(MaskExceptions)
  18 C(MaskExceptions):
  19         fnstenv fpenv
  20         orl             $0x3F,fpenv
  21         fldenv  fpenv
  22
  23         ret
  24
  25 #if 0
  26 .globl C(unmaskexceptions)
  27 C(unmaskexceptions):
  28         fnstenv fpenv
  29         andl            $0xFFFFFFE0,fpenv
  30         fldenv  fpenv
  31
  32         ret
  33 #endif
  34
  35         .data
  36
  37         .align  4
  38 .globl  ceil_cw, single_cw, full_cw, cw, pushed_cw
  39 ceil_cw:        .long   0
  40 single_cw:      .long   0
  41 full_cw:        .long   0
  42 cw:                     .long   0
  43 pushed_cw:      .long   0
  44
  45         .text
  46
  47 .globl C(Sys_LowFPPrecision)
  48 C(Sys_LowFPPrecision):
  49         fldcw   single_cw
  50
  51         ret
  52
  53 .globl C(Sys_HighFPPrecision)
  54 C(Sys_HighFPPrecision):
  55         fldcw   full_cw
  56
  57         ret
  58
  59 .globl C(Sys_PushFPCW_SetHigh)
  60 C(Sys_PushFPCW_SetHigh):
  61         fnstcw  pushed_cw
  62         fldcw   full_cw
  63
  64         ret
  65
  66 .globl C(Sys_PopFPCW)
  67 C(Sys_PopFPCW):
  68         fldcw   pushed_cw
  69
  70         ret
  71
  72 .globl C(Sys_SetFPCW)
  73 C(Sys_SetFPCW):
  74         fnstcw  cw
  75         movl    cw,%eax
  76 #if     id386
  77         andb    $0xF0,%ah
  78         orb             $0x03,%ah       // round mode, 64-bit precision
  79 #endif
  80         movl    %eax,full_cw
  81
  82 #if     id386
  83         andb    $0xF0,%ah
  84         orb             $0x0C,%ah       // chop mode, single precision
  85 #endif
  86         movl    %eax,single_cw
  87
  88 #if     id386
  89         andb    $0xF0,%ah
  90         orb             $0x08,%ah       // ceil mode, single precision
  91 #endif
  92         movl    %eax,ceil_cw
  93
  94         ret
  95