source: xtideuniversalbios/trunk/Assembly_Library/Src/Util/Math.asm@ 238

Last change on this file since 238 was 181, checked in by krille_n_@…, 13 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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