Hello! I'm trying to swap some characters in this form, in Linux+NASM:
abc -> cab -> bca -> abc
I tried the following method
section .data
string: db 'abc',10
strlen: equ $-string
section .text
global _start
_start:
mov ebx,1
add ebx,string
mov string, [ebx]But it gives me these errors:
error: invalid combination of opcode and operands
Please help me understanding what it means and how to do it in the best way.
Hello! I'm trying to swap some characters in this form, in Linux+NASM:
abc -> cab -> bca -> abcI tried the following method
section .data string: db 'abc',10 strlen: equ $-string section .text global _start _start: mov ebx,1 add ebx,string mov string, [ebx]But it gives me these errors:
error: invalid combination of opcode and operands
Please help me understanding what it means and how to do it in the best way.
mov ebx,1
add ebx,string
mov string, [ebx]On the third line you're trying to copy the second character of string into the address of the first character in string. I don't think that's your actual intention though.
that code is all wrong. I have solved the problem already :
section .bss
swap resb 3
%macro print 2
mov eax, 4
mov ebx, 1
mov ecx, %1
mov edx, %2
int 80h
%endmacro
%macro toswap 1
mov eax, [%1]
mov [swap],eax
mov eax, [%1+1]
mov [swap+1],eax
mov eax, [%1+2]
mov [swap+2],eax
%endmacro
section .data
alfa db 'abc'
alfalen equ $-alfa
section .text
global _start
_start:
mov si,3
mov bp,1
print alfa, alfalen
.loop:
toswap alfa
mov ah, [swap]
mov bx, [swap+1]
mov al, [swap+2]
mov [alfa],al
mov [alfa+1],ah
mov [alfa+2],bx
inc bp
print alfa, alfalen
test bp,si
jnz .loop
;***EXIT***
mov eax,1 ; (sys_exit)
mov ebx,0 ; Exit with return code of 0 (no error)
int 80hLinks that helped me
Linux Assembly - http://www.linuxassembly.org
NASM Manual ( available in doc/html directory of source )
Assembly Programming Journal - http://asmjournal.freeservers.com/
Mammon_'s textbase - http://www.eccentrica.org/Mammon/sprawl/textbase.html
Art Of Assembly - http://webster.cs.ucr.edu/Page_asm/ArtOfAsm.html
Sandpile - http://www.sandpile.org
comp.lang.asm.x86
NASM - http://www.cryogen.com/Nasm
Asmutils-HOWTO - doc/ directory of asmutils
http://maven.smith.edu/~thiebaut/ArtOfAssembly/artofasm.html
http://www.ibm.com/developerworks/library/l-gas-nasm.html ///very helpful
http://maven.smith.edu/~thiebaut/ArtOfAssembly/artofasm.html
http://www.laynetworks.com/assembly%20tutorials3.htm
http://www.nasm.us/
Be blessed
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