source: xtideuniversalbios/trunk/Assembly_Library/Src/Util/Math.asm @ 181

Last change on this file since 181 was 181, checked in by krille_n_@…, 12 years ago

Changes to all parts of the project:

  • Size optimizations.
  • Added a define (EXCLUDE_FROM_XTIDECFG) to exclude unused library code from XTIDECFG.
  • Tried to minimize time spent with interrupts disabled.
  • Some minor attempts to improve speed (reordering instructions etc).
  • Tried to improve readability, did some cleanup and fixed some errors in comments.
File size: 1.5 KB
RevLine 
[172]1; Project name  :   Assembly Library
2; Description   :   Functions for register operations.
3
4
5; Section containing code
6SECTION .text
7
8;--------------------------------------------------------------------
9; Math_DivQWatSSBPbyCX
10;   Parameters:
11;       [SS:BP]:    64-bit unsigned divident
12;       CX:         16-bit unsigned divisor
13;   Returns:
14;       [SS:BP]:    64-bit unsigned quotient
15;       DX:         16-bit unsigned remainder
16;   Corrupts registers:
17;       AX
18;--------------------------------------------------------------------
[181]19%ifndef EXCLUDE_FROM_XTIDECFG   ; Not used in XTIDECFG
[172]20ALIGN JUMP_ALIGN
[181]21Math_DivQWatSSBPbyCX:
[172]22    xor     dx, dx
23    mov     ax, [bp+6]      ; Load highest divident WORD to DX:AX
24    div     cx
25    mov     [bp+6], ax      ; Store quotient
26
27    mov     ax, [bp+4]
28    div     cx
29    mov     [bp+4], ax
30
31    mov     ax, [bp+2]
32    div     cx
33    mov     [bp+2], ax
34
35    mov     ax, [bp]
36    div     cx
37    mov     [bp], ax
38    ret
[181]39%endif
[172]40
41
42;--------------------------------------------------------------------
43; Math_DivDXAXbyCX
44;   Parameters:
45;       DX:AX:  32-bit unsigned divident
46;       CX:     16-bit unsigned divisor
47;   Returns:
48;       DX:AX:  32-bit unsigned quotient
49;       BX:     16-bit unsigned remainder
50;   Corrupts registers:
51;       Nothing
52;--------------------------------------------------------------------
[181]53%ifndef EXCLUDE_FROM_XTIDE_UNIVERSAL_BIOS OR EXCLUDE_FROM_XTIDECFG
[172]54ALIGN JUMP_ALIGN
[181]55Math_DivDXAXbyCX:   ; This is currently unused (dead code)
[174]56    xor     bx, bx
57    xchg    bx, ax
58    xchg    dx, ax
[172]59    div     cx
60    xchg    ax, bx
61    div     cx
62    xchg    dx, bx
63    ret
[174]64%endif
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