flat assembler
Message board for the users of flat assembler.

flat assembler > Main > What is FASM's equivalent of local or locals?

Author
Thread Post new topic Reply to topic
ar18



Joined: 07 Feb 2018
Posts: 3
=== snippet ===
start:
locals dlg
=== snippet ===

...gives the following error message...

error: illegal instruction.

I didn't know "locals" or "local" was an illegal instruction. What is FASM's equivalent of local or locals?
Post 13 Feb 2018, 13:31
View user's profile Send private message Reply with quote
fasmnewbie



Joined: 01 Mar 2011
Posts: 523
locals / local is a high-level statement. Not part of FASM's internal core nor it is part of the Instruction Set. It is however a support macro usually ships with FASM distribution as separate include files that support high-level statements such PROC, etc... notably for Windows.

Code:
format SomeFormat
include 'win32axp.inc'
or
include 'proc32.inc'...

proc start
   locals 
       hello db 'Hello',0ah,0
   endl
   ...
   ret
endp    

or something like that
Post 14 Feb 2018, 00:11
View user's profile Send private message Visit poster's website Reply with quote
ar18



Joined: 07 Feb 2018
Posts: 3
What you are saying doesn't match any of the text in the FASM Programmer's Manual, but I tried it anyways and it doesn't work. Maybe there is something else in the program that is keeping it from working:

Code:
format PE64 GUI 5.0
entry start
;============================================= DEFINES
include 'include/encoding/utf8.inc'
include 'include/win64a.inc'
include 'include/macro/proc64.inc'

BUTTON1 = '1'
;MASK_FLOAT = '[+/-]?(/d+/.?/d*|/./d+)'
MACRO dll %fnRtn,%fn,%p1,[%p] {
        reverse
                push %p
        forward
                call %fn
                mov %fnRtn,rax
        }
dqTest dq  0
;============================================== START
section '.text' code readable executable

start proc
        local dlg
        dll [dqTest],fnTest,rax,0 
        ret
        
proc fnTest
        ret
        endp

section '.idata' data import readable
library crt,"pocrt64.dll"
import crt, \
        fclose,"fclose", \
        ferror,"ferror", \
        fopen,"fopen", \
        fread,"fread", \
        free,"free", \
        fseek,"fseek", \
        ftell,"ftell", \
        fwrite,"fwrite", \
        malloc,"malloc", \
        realloc,"realloc", \
        strcan,"strcan", \
        strlen,"strlen", \
        strrchr,"strrchr", \
        strtok,"strtok"    


Notice the string that I commented out at the beginning? The MASK_FLOAT = '[+/-]?(/d+/.?/d*|/./d+)'? It came from an actual program I wrote, assembled, and ran without a problem. What's wrong with that string? FASM won't process it without giving an error that makes no sense.

The FASM Progammer's Manual (pg 113, version 1.72) says that LOCAL will work but only if I specify PROC first, but I can't find any way to get LOCAL or PROC to work with start.
Post 14 Feb 2018, 20:28
View user's profile Send private message Reply with quote
fasmnewbie



Joined: 01 Mar 2011
Posts: 523
@ar

I don't understand what your program is for, but it looks like you're porting from NASM. I can't help you much with the content but I can make structural suggestions / corrections to cut down the number of errors you're having;


Code:
format PE64 GUI 5.0   ;Are you sure it's for windows, not console?
entry start 

include 'include/encoding/utf8.inc'     ;'encoding/utf8.inc'
include 'include/win64a.inc'              ;'win64axp.inc'
include 'include/macro/proc64.inc'    ;not needed. Already included above

BUTTON1 = '1' 
;MASK_FLOAT = '[+/-]?(/d+/.?/d*|/./d+)'  ; use equ 
MACRO dll %fnRtn,%fn,%p1,[%p] {          ;loose that %, just for code clarity.  
        reverse 
                push %p 
        forward 
                call %fn 
                mov %fnRtn,rax 
        } 

dqTest dq  0 

section '.text' code readable executable 

start proc          ;==> proc start
        local dlg   ;incomplete syntax. Is it a DB? DQ? See my example above.
        dll [dqTest],fnTest,rax,0  
        ret 
                        ;==> missing endp
proc fnTest 
        ret 
        endp    
Post 14 Feb 2018, 21:05
View user's profile Send private message Visit poster's website Reply with quote
ar18



Joined: 07 Feb 2018
Posts: 3
"It looks like you're porting from NASM"

Remind me to never try NASM then Very Happy

I actually have used MASM, MASM32, and GoASM.

;Are you sure it's for windows, not console?

It's actually just a test to see how easy it is to write a program for FASM. I won't rewrite code for a new language until I see how well it works and how well it is documented first.

; use equ

Why don't I need to use equ for BUTTON = '1'? What is FASM's rule behind that?

;loose that %, just for code clarity.

GoASM suggested using it for code clarity Very Happy

;incomplete syntax. Is it a DB? DQ? See my example above.

I can see that now, but following your example above didn't work. This is the actual FASM rule:

1) Use :dword, :qword, :byte, etc for LOCAL
2) Use dd, dq, db, etc for LOCALS ... ENDL

Anything else will not work. Also not sure if any of the above is case sensitive. I'm kind of disappointed that I can't have a default size, such as qword for PE64 and dword for PE32. I have programs where certain functions have up to thirty local vars, and with FASM it will bloat it to twice the size it was before. I do like the macro style LOCALS, since you can initialize values at the same time you define them.

The following code compiles now, so thank you for your input:

Code:
format PE64 GUI 5.0
entry start
;============================================== DEFINES
include 'include/encoding/utf8.inc'
include 'include/win64a.inc'

BUTTON1 = '1'
MASK_FLOAT equ '[+/-]?(/d+/.?/d*|/./d+)'
MACRO dll fnRtn,fn,p1,[p] {
        reverse
                push p
        forward
                call fn
                mov fnRtn,rax
        }
dqTest dq  0
;=============================================== START
section '.text' code readable executable

proc start
        local dlg:QWORD
        dll [dqTest],fnTest,rax,0 
        ret
        endp

proc fnTest
        locals
                dlg dq ?
                endl
        ret
        endp

section '.idata' data import readable
library crt,"pocrt64.dll"
import crt, \
        fclose,"fclose", \
        ferror,"ferror", \
        fopen,"fopen", \
        fread,"fread", \
        free,"free", \
        fseek,"fseek", \
        ftell,"ftell", \
        fwrite,"fwrite", \
        malloc,"malloc", \
        realloc,"realloc", \
        strcan,"strcan", \
        strlen,"strlen", \
        strrchr,"strrchr", \
        strtok,"strtok"    


I will be doing a few more tests, one of them to test the UTF8 functionality (with or w/o BOM).

PS -- Obviously FASM has a method for inserting calls to DLLs, but does it have the same built-in functionality for inserting code from static libraries?
Post 15 Feb 2018, 01:04
View user's profile Send private message Reply with quote
Furs



Joined: 04 Mar 2016
Posts: 1203
In FASM, you have two stages. First is preprocessor, which is text substitution (but much more powerful than the C preprocessor, if you're familiar with that gimped one).

EQU and DEFINE are preprocessor directives, so they can do text substitution (i.e. replace their use with anything). DEFINE is same as EQU except it doesn't substitute other symbolic constants (defined with equ or define) in its own definition (i.e. it does "raw" defines).

BUTTON = '1' on the other hand is an assembler-stage directive, not preprocessor. It is numerical only. Also, assembly-time constants like this are very powerful since they can be evaluated in multiple passes (example: defining it at the end will work, FASM will do another pass for it, and optimize if something changed). In this case '1' is not a string, it's the numerical value of 1 in ASCII.

Just like in C, '1' is a numerical value (character) not a string.
Post 15 Feb 2018, 13:44
View user's profile Send private message Reply with quote
Display posts from previous:
Post new topic Reply to topic

Jump to:  


< Last Thread | Next Thread >
Forum Rules:
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


Copyright © 1999-2018, Tomasz Grysztar.

Powered by rwasa.