После вызова функции setup_ivt получено сообщение об ошибке: Trying to execute code outside RAM or ROM at 0x00000000000a0000
Программа реального времени x86 запускается из загрузчика, который считывает в память следующие сектора (поместите чтение в секторах из 0x7E00, сразу после того, где находится загрузочный сектор).
Сразу после метки main ошибка возникает при использовании call setup_ivt.Программа работает нормально, если поместить тело функции setup_ivt непосредственно вместо использования call.Что-то не так с ret?Спасибо, Майкл.
.code16 #! tell the assembler to generate 16-bit code
.globl _start
.section .text
_start:
cli
xor %ax, %ax
mov %ax, %ds
mov %ax, %es
mov %ax, %fs
mov %ax, %gs
mov %ax, %ss
mov $_start, %sp
sti
cld
load_to_RAM_from_2nd_Sector:
mov $0x00, %edx # see section: Int 13/AH=02h - DISK - READ SECTOR(S) INTO MEMORY
mov $0x02, %ecx
mov $0x7E0, %ax # Read in the 2nd sector from disk to memory 0x7E00
mov %ax, %es
xor %bx, %bx
movb $0x02, %ah
movb SYSLEN, %al
int $0x13
jnc ok_load
die:jmp die
ok_load:
cli
mov $0x7E0, %ax
mov %ax, %ds
xor %ax, %ax
mov %ax, %es
mov $0x1000, %cx
xor %esi, %esi
xor %edi, %edi
rep movsw
sti
ljmp *head_offset
# data region
SYSLEN: .word 0x11 # less than 17 sector of program head
head_segment:.word 0x0
head_offset: .word 0x7E00
.org 510
.word 0xAA55 # last 16 bits of first 512 bytes on disk
Second_Sector:
cli # Turn off interrupts
xor %ax, %ax # Initialize the segments, set the stack to grow down from
mov %ax, %ds # start of bootloader at _start. SS:SP=0x0000:0x7c00
mov %ax, %es
mov %ax, %fs
mov %ax, %gs
mov %ax, %ss
mov $0x7C00, %sp
cld # Set direction flag forward for string instructions
main: # main program starts
call setup_ivt
# pushl %eax
# pushl %edx
# pushw %es
# movl $0, %edx
# movl $0, %eax
# movw %ax, %es
# lea ignore_int, %ax
#loop_ivt:
# movl %eax, %es:(,%edx,4)
# addl $1, %edx
# cmpl $256, %edx
# jb loop_ivt
# popw %es
# popl %edx
# popl %eax
#jmp .
movl $system_interrupt, %eax # set IVT int 0x80
movl %eax, 0x0200(,1)
movl $timer_interrupt, %eax # set timer handler
movl %eax, 0x0020(,1) # timer part 1
movb $0x36, %al # 8293 timer setting
movl $0x43, %edx
outb %al, %dx
movl $11930, %eax # about every 1/100 second
movl $0x40, %edx
outb %al, %dx
movb %ah, %al
outb %al, %dx
sti
jmp .
write_char: # set %ax, SCN_SEL,scn_pos before call
pushl %ebx # put %ebx to stack
pushw %es
movw SCN_SEL, %es
movl scn_pos, %ebx
cmpl $2000, %ebx
jb wr1
xor %ebx, %ebx
wr1: shll $1, %ebx # time %bx by 2
movw %ax, %es:(%bx)# write 2 bytes to screen, 1 character displayed
shrl $1, %ebx
addl $1, %ebx
movl %ebx, %cs:scn_pos
popw %es
popl %ebx # recover %ebx from stack
ret
system_interrupt: #system_interrupt handler to call write_char and iret;
push %ds
pushl %edx
pushl %ecx
pushl %ebx
pushl %eax
call write_char
popl %eax
popl %ebx
popl %ecx
popl %edx
pop %ds
iret #end of system_interrupt
timer_interrupt:
movb $0x20, %al
outb %al, $0x20
movb $1, %al
cmpb %al, %cs:current
je t0
movb $1, %cs:current
jmp task1
jmp t1
t0: movb $0, %cs:current
jmp task0
t1:
iret
task0:
sti
movb $0x0A, %ah # set the colour attributes
movb $67, %al
int $0x80
movl $0xFFF, %ecx # pause for some time
ta2: loop ta2
jmp task0
task1:
sti
movb $0x0D, %ah # set the colour attributes
movb $83, %al
int $0x80
movl $0xFFF, %ecx
ta3: loop ta3
jmp task1
ignore_int:
pushl %eax
movb $0x0E, %ah
movb $88, %al
int $0x80
popl %eax
iret
setup_ivt:
pushl %eax
pushl %edx
pushw %es
movl $0, %edx
movl $0, %eax
movw %ax, %es
lea ignore_int, %ax
loop_set_ivt:
movl %eax, %es:(,%edx,4)
addl $1, %edx
cmpl $256, %edx
jb loop_set_ivt
popw %es
popl %edx
popl %eax
ret
SCN_SEL: .word 0xb800 #! memory number where colour text starts
scn_pos: .long 0x0 # 2 bytes to save current screen postion
current: .byte 0x1
# as boot0.s -o boot0.o;ld -o boot0 boot0.o -Ttext=0x7c00 --oformat=binary;sudo qemu-system-x86_64 -drive format=raw,file=boot0,index=0,if=floppy -cpu max
# as boot1.s -o boot1.o;ld -o boot1 boot1.o -Ttext=0x7c00 --oformat=binary;sudo qemu-system-x86_64 -drive format=raw,file=boot1,index=0,if=floppy -cpu max