Author Topic: Getting started. (Read 11752 times)

epl692 · « **on:** July 15, 2016, 04:09:29 PM »

So I have been trying to learn the basics of nasm programing. I started by using http://forum.nasm.us/index.php?topic=2062.0 as a base. I am trying to capture text from the user and put it into memory. I just can't seem to figure out how to mov it.

Code: [Select]

;--------------------------------------------
; Copyright (c)2015,2016 Soffian Abdul Rasad
; All rights reserved
; For Linux64 - Arguments in RAX,RBX,...
;	      - Return in RAX,RBX...
; Read licence.txt
;--------------------------------------------
; Compile : nasm -f elf64 thisfile.asm
; Link	  : ld thisfile.o -o thisfile
; Run	  : ./thisfile
;--------------------------------------------
global _start

section .data
msg db 'Hello world,',0
welcome db 'This is Eric',0
prompt1 db 'What is your name? ',0

s dq 45.667


section .bss
dummy resq 1
name resw 10
	
section .text
_start:

	mov	rax,msg
	call	prnstrz
	call	newline
	mov	rax,welcome
	call	prnstrz
	call	newline
	mov	rax,prompt1
	call	prnstrz
	call	readstr
	;; 	text is kept in rax
	;;	mov	[name],rax	
	mov	rax,name
	call	newline
	call	prnstrz
	call	newline
	;practice coding here

	
call exit

...
Full Source: http://sdf.org/~epl692/eric.asm

soulvomit · « **Reply #1 on:** July 18, 2016, 07:40:10 AM »

Hi,

readstr is not part of the source code you linked? where do you get this subroutine from?

Cheers

Bryant Keller · « **Reply #2 on:** July 24, 2016, 03:55:34 AM »

Quote from: soulvomit on July 18, 2016, 07:40:10 AM

readstr is not part of the source code you linked? where do you get this subroutine from?

It's in the updated version of stressful's code (same thread):

Quote from: stressful on May 05, 2016, 08:40:52 PM

Code: [Select]
prnchr prnchrs prnchar prnstr prnstrz prnstrd readch readchr readstr delay mem_alloc mem_free file_new file_open file_read file_write file_close file_size exit exitp newline halt prnstreg prnreg prnregd prnregdu dumpreg dumpregd dumpregdu dumpseg dumpenv flags stackview memview memviewc mem_reset mem_set mem_copy mem_load opsize opcode prnint prnintu prnhex prnhexu prnoct prnoctu prnbin prnbinu prnbinf prnbinb fpbin fpbind prndbl prndble prndblr prnflt prnfltr prndblx dblsplit fpdinfo fpfinfo dec2str dec2stru hex2str hex2stru dbl2str readint readflt readdbl fpu_stack fpu_sflag fpu_cflag fpu_tag fpu_reg fpu_copy fpu_precision fpu_round sse_round sse_flags prnxmm dumpxmm clearxmm prnymm dumpymm clearymm prnintd prnintw prnintb str2int str2dbl str2flt dbl2int int2dbl rndigit rndint isint digiti digith factorial powint pow2 iseven isodd bconv bitfield addf subf mulf divf pow sqroot log10 ln10 deg2rad rad2deg sine tangent cosine sincos atangent chr_isdigit chr_isalpha chr_isupper chr_islower chr_toupper chr_tolower chr_chcase chr_find chr_count chr_shuffle ascii str_copy str_length str_cmpz str_cmp str_toupper str_tolower str_reverse str_trim str_wordcnt str_token str_find str_findz str_appendz str_append sort_byte sort_int sort_dbl sort_dblx sort_flt aprndbl aprndblx aprnflt aprnint

Quote from: epl692 on July 15, 2016, 04:09:29 PM

So I have been trying to learn the basics of nasm programing. I started by using http://forum.nasm.us/index.php?topic=2062.0 as a base. I am trying to capture text from the user and put it into memory. I just can't seem to figure out how to mov it.

I'm not really familiar with his codebase, but a quick look at his source for nsm64.asm gives a good hint as to what your problem is.

Code: [Select]

;-------------------------------
;readstr(1)/1
;Get string from keyboard
;and 0-ended it
;-------------------------------
;RAX	: Address of the buffer
;-------------------------------
;Ret	: # of bytes entered in RAX
;	: String in buffer
;Note	: Use with prnstrz
;	: Buffer is of type DB/RB
;	: Buffer must be large enough
;	: Ret -1 signals error
;-------------------------------

So what this function does is takes as an argument (in RAX) the address of your memory location, the memory location gets updated with the string that was entered by the user, and then RAX is updated with the number of bytes read from the user. So in your code, it should look something like this:

Code: [Select]

...
	mov	rax, prompt1
	call	prnstrz
	mov	rax, name
	call	readstr
	call	newline
	mov	rax, name
	call	prnstrz
...

Regards,
Bryant Keller

NASM - The Netwide Assembler

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Author Topic: Getting started. (Read 11752 times)

epl692

Getting started.

soulvomit

Re: Getting started.

Bryant Keller

Re: Getting started.