func.s

一个微型操作系统源码

[segment .text]
[BITS 32]

%imacro EXPORT 1
  GLOBAL %1
  align 4
  %1:
%endmacro

; unsigned char get_byte(unsigned short sel, unsigned long addr)
EXPORT get_byte
	mov 	ax, [esp+4]
        mov 	gs, ax
        mov 	edx, [esp+8]
        xor 	eax, eax
        mov 	al, byte [gs:edx]
        ret

; unsigned short get_word(unsigned short sel, unsigned long addr)
EXPORT get_word
	mov 	ax, [esp+4]
        mov 	gs, ax
        mov 	edx, [esp+8]
        xor 	eax, eax
        mov 	ax, word [gs:edx]
        ret

; unsigned long get_long(unsigned short sel, unsigned long addr)
EXPORT get_long
	mov 	ax, [esp+4]
        mov 	gs, ax
        mov 	edx, [esp+8]
        mov 	eax, dword [gs:edx]
        ret

; void put_byte(unsigned short sel, unsigned long addr, unsigned char val)
EXPORT put_byte
	mov 	ax, [esp+4]
        mov 	gs, ax
        mov 	edx, [esp+8]
        mov 	al, byte [esp+12]
        mov 	[gs:edx], al
        ret

; void put_word(unsigned short sel, unsigned long addr, unsigned short val)
EXPORT put_word
	mov 	ax, [esp+4]
        mov 	gs, ax
        mov 	edx, [esp+8]
        mov 	ax, word [esp+12]
        mov 	[gs:edx], ax
        ret

; void put_long(unsigned short sel, unsigned long addr, unsigned long val)
EXPORT put_long
	mov 	ax, [esp+4]
        mov 	gs, ax
        mov 	edx, [esp+8]
        mov 	eax, [esp+12]
        mov 	[gs:edx], eax
        ret