1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
|
[global Start]
[BITS 16]
[ORG 0x7C00]
; Simple test of the NASM parser
; Data section, initialized variables
SECTION .data
fmt: db "a=%d, eax=%d", 10, 0 ; the printf format
a: dd 5 ; int a = 5
%macro IRQ 2
global irq%1
irq%1:
cli
push byte 0 ; push a dummy error code
push byte %2 ; push the IRQ number
jmp irq_common_stub
%endmacro
extern printf ; the C function to be called
; Code section
SECTION .text
global main ; the standard gcc entry point
main:
push ebp
mov ebp, esp
mov eax, [a]
add eax, 2
push 'a'
push dword [a] ; value of variable a
push dword fmt ; address of ctrl string
call printf ; call C function
add esp, 12
mov esp, ebp ; takedown stack frame
pop ebp
mov eax, 0 ; normal, no error, return value
ret ; return
irq_common_stub:
pusha ; pushes all general-purpose registers
mov ax, ds ; lower 16-bits of eax = ds
mov ax, 0x10 ; load the kernel data segment descriptor
mov ds, ax
popa ; pops all general-purpose registers
add esp, 8 ; cleans up the pushed error code and pushed irq number
sti ; (re)-enable interrupts "set interrupt flag"
iret ; pops CS, EIP, EFLAGS, SS, and ESP
%assign i 0
%rep 16
IRQ i, i+32
%assign i i+1
%endrep
mov eax, [eax]
mov eax, [eax + ebx]
mov eax, [eax + ebx*2]
mov eax, [eax + 10]
mov eax, [eax + ebx*2 + 10]
|
