source: xtideuniversalbios/trunk/Assembly_Library/Inc/Delay.inc@ 255

Last change on this file since 255 was 247, checked in by aitotat@…, 13 years ago

Changes to Assembly Library:

  • Delay functions are no longer required by reboot functions when building XTIDE Universal BIOS.
File size: 1.3 KB
Line 
1; Project name : Assembly Library
2; Description : Delay macros.
3%ifndef DELAY_INC
4%define DELAY_INC
5
6;--------------------------------------------------------------------
7; Clears prefetch queue by jumping to next instruction.
8; This delays much more than nop instruction of fast systems.
9;
10; JMP_DELAY
11; Parameters
12; Nothing
13; Returns:
14; Nothing
15; Corrupts registers:
16; Nothing
17;--------------------------------------------------------------------
18%macro JMP_DELAY 0
19 jmp SHORT %%NextInstruction
20%%NextInstruction:
21%endmacro
22
23
24;--------------------------------------------------------------------
25; Mimimun delays (without fetching) with some CPU architectures:
26; 8088/8086: 17 cycles for jump + 5 cycles for last comparison
27; 286: 10 cycles for jump + 4 cycles for last comparison
28; 386: 13 cycles for jump + ? cycles for last comparison
29; 486: 7 cycles for jump + 6 cycles for last comparison
30;
31; DELAY_WITH_LOOP_INSTRUCTION
32; Parameters
33; CX: Loop iterations (0 is maximum delay with 65536 iterations)
34; Returns:
35; Nothing
36; Corrupts registers:
37; CX
38;--------------------------------------------------------------------
39%macro DELAY_WITH_LOOP_INSTRUCTION 0
40%%StartOfLoop:
41 loop %%StartOfLoop
42%endmacro
43
44
45%endif ; DELAY_INC
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