nasm

问题 I just started messing around with assembly language and I tried to print the number 9 on console. Here is what I wrote: global _main section .data digit equ 9 section .bss section .text _main: mov edx, 1 mov ecx, digit add ecx, 48 mov ebx, 1 mov eax, 4 int 21h ret I know I can do it using extern _printf but I want try it with interrupts. I thought 21h is a windows interrupt. So, what interrupt code should I use? 回答1: Here's an example from a course that I teach. This is a raw bootsector that

问题 I'm attempting to assemble some 32-bit code using NASM and GCC on a 64-bit system. I use the following two commands nasm -f elf32 -g -F stabs coc.asm gcc -m32 -o coc coc.o NASM appears to do fine, but LD complains: /usr/bin/ld: cannot find crt1.o: No such file or directory /usr/bin/ld: cannot find crti.o: No such file or directory /usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/4.6.1/libgcc.a when searching for -lgcc /usr/bin/ld: cannot find -lgcc /usr/bin/ld: skipping

问题 I'm using nasm under ubuntu. By the way i need to get single input character from user's keyboard (like when a program ask you for y/n ?) so as key pressed and without pressing enter i need to read the entered character. I googled it a lot but all what i found was somehow related to this line ( int 21h ) which result in "Segmentation Fault". Please help me to figure it out how to get single character or how to over come this segmentation fault. 回答1: It can be done from assembly, but it isn't

问题 I'm using nasm under ubuntu. By the way i need to get single input character from user's keyboard (like when a program ask you for y/n ?) so as key pressed and without pressing enter i need to read the entered character. I googled it a lot but all what i found was somehow related to this line ( int 21h ) which result in "Segmentation Fault". Please help me to figure it out how to get single character or how to over come this segmentation fault. 回答1: It can be done from assembly, but it isn't

问题 I am trying to write a simple assembly code to spit out hex values to the screen. There are two files print_screen.asm which is working with other modules. I think the problem is in my logic when trying to convert hex to string. My code is: [org 0x7c00] xor dx,dx xor ax,ax xor bx,bx mov dx, 0x1fb6 call print_hex jmp endi; print_hex: pusha mov ax,0x0001 and ax,dx add ah,48 mov byte [HEX_OUT+5],ah mov ax,0x0010 and ax,dx add ah,48 mov byte [HEX_OUT + 4],ah mov ax,0x0100 and ax,dx add ah,48 mov

问题 For my Question when I tried to create a example of NASM under ubuntu 64-bit version and execute it after assembled and linked into ELF. It return error messages as below when I execute NASM -f elf64 -o firstasm.o firstasm.asm ld -o firstasm firstasm.o firstasm Segmentation fault (core dumped) My NASM code would be below where I tried to perform simple write() and exit() function section .data ;Data segment msg db "This line is test", 0x0a section .text ;text segment global _start ;Default

问题 So I have to strings s1 and s2 and I have two obtain the string d that contains the maximum numbers for each of the positions of s1 and s2. For example: S1: 1, 3, 6, 2, 3, 10 S2: 6, 3, 11, 1, 2, 5 D: 6, 3, 11, 2, 3, 10 So this is the code bits 32 global start extern exit,printf import exit msvcrt.dll import printf msvcrt.dll segment data use32 class=data format db "%s",0 s1 db "1","3","6","2","3","10" l equ $-s1 s2 db "6","3" ,"11","1","2", "5" d times l db 0 segment code use32 class=code

问题 I'm trying to do a simple division: mov ebx, 10 mov eax, 1111111111 ;(10 times) mov edx, 0 idiv bx Supposedly I want to get the following results: edx = 1 eax = 111111111 (9 times) But the results I'm getting are: edx = 7 eax = 1111098720 Does anyone know what the problem might be? Thanks 回答1: mov ebx, 10 mov eax, 1111111111 ;(10 times) mov edx, 0 idiv bx What immediately strikes me is that you setup all registers for 32 -bit operation but then perform a 16 -bit division. Changing it to the

问题 I am trying to print a string in Q Emulator using NASM. My code is as below: mov bx,HELLO mov ah, 0x0e int 0x10 HELLO: db 'Hello', 0 jmp $ times 510-($-$$) db 0 dw 0xaa55 However when I compile this code, the output that I get is UU Can anyone please tel me why this is so? And how to get the required string as output? Thanks in advance. 回答1: ALRIGHT SO here is a thingamabob to your question In order to load the string, you must move it into si (don't really want to go to deep but just do it).

问题 I'm writing a project and wanted to make one, good makefile. At some point I noticed that it doesn't work for multiple .asm files, I did some research and modified my file, so it looks like this: PROJDIRS := kernel lib ASMFILES := $(shell find $(PROJDIRS) -type f -name "*.asm") SRCFILES := $(shell find $(PROJDIRS) -type f -name "*.c") HDRFILES := $(shell find $(PROJDIRS) -type f -name "*.h") ASMOBJCT := $(patsubst %.asm,%.o,$(ASMFILES)) OBJFILES := $(patsubst %.c,%.o,$(SRCFILES)) TSTFILES :=