fasm(g) tolerate of underscore in numbers ?

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jmg

Joined: 18 Sep 2016
Posts: 62

jmg 19 Sep 2016, 09:02

In various tools, it is now more common for parsers to tolerate underscore within numbers.
This makes source more readable by spacing the fields to match the contents.

eg

MOV A,#0000_1111b
MOV A,#00_11_1111b

MOV DPTR,#1_23_4H

Can that tolerate underscore within numbers feature be added to Fasm(g) ?

I see it is already smart enough to allow all 3 common HEX formats

DEC 0x55r
DEC 55H
DEC $55

19 Sep 2016, 09:02

Tomasz Grysztar

Joined: 16 Jun 2003
Posts: 8349
Location: Kraków, Poland

Tomasz Grysztar 19 Sep 2016, 10:00

In fasm traditionally ' character was used for this purpose:

Code:

db 0000'1111b

But supporting _ as an alternative should not cause any problems, so I may as well add it.

In the meantime, just for fun I'm going to demonstrate how to preprocess source text to convert such numbers with a macro:

Code:

macro convert_token out,token& 
        local t,a
      t db `token
        load a:byte from t
        if a >= '0' & a <='9'
                repeat $-t
                        load a:byte from t+%-1
                        if a = "_"
                                store "'":byte at t+%-1
                        end if
                end repeat
        end if
end macro

macro ? line&
        local buffer,command
        virtual at 0
        define out
        define buffer line
        while 1 
                match car cdr, buffer 
                        convert_token out,car 
                        match car_= cdr_, buffer
                                match =car,car_
                                        db ' '
                                end match
                        end match
                        define buffer cdr
                else match car, buffer
                        convert_token out,car 
                        break 
                else 
                        break 
                end match 
        end while
        load command:$ from 0
        end virtual
        eval command
end macro  


db 0000_1111b

I originally wrote a variant of this macro for shoorick to convert octal numbers ending with "Q" to ones ending with "O", but then I added support for "Q" numbers into fasmg anyway.

Last edited by Tomasz Grysztar on 19 Sep 2016, 10:36; edited 2 times in total

19 Sep 2016, 10:00

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20289
Location: In your JS exploiting you and your system

revolution 19 Sep 2016, 10:04

fasm uses the single quote character (') for number separation.

fasmarm uses the more common underscore character (_) for number separation.

19 Sep 2016, 10:04

Tomasz Grysztar

Joined: 16 Jun 2003
Posts: 8349
Location: Kraków, Poland

Tomasz Grysztar 19 Sep 2016, 10:58

revolution wrote:

fasm uses the single quote character (') for number separation.

fasmarm uses the more common underscore character (_) for number separation.

Well, I might add it into fasm, too.

Already added to fasmg.

19 Sep 2016, 10:58

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20289
Location: In your JS exploiting you and your system

revolution 19 Sep 2016, 11:01

Tomasz Grysztar wrote:

Well, I might add [_] into fasm, too.

Yay.

19 Sep 2016, 11:01

jmg

Joined: 18 Sep 2016
Posts: 62

jmg 19 Sep 2016, 19:57

Tomasz Grysztar wrote:

Already added to fasmg.

Great

Tested this, and it also fixed an issue of not allowing > 8bit binary strings.
Now, only if the number overflows the field, does an error result = Good.

flat assembler g version 0.98.1474353977

Code:

        dd (100000_0010b shl 22)
        dd (1111_1010_0101_0111_0110_0101_0100_0011b)
;       dd (1_1111_1010_0101_0111_0110_0101_0100_0011b)   ; flags, as is > 32b
        dq (1110_1111_1010_0101_0111_0110_0101_0100_0011_0010_0001b)

19 Sep 2016, 19:57

Tomasz Grysztar

Joined: 16 Jun 2003
Posts: 8349
Location: Kraków, Poland

Tomasz Grysztar 21 Sep 2016, 17:21

To sum things up:l fasmg now supports three ways of separating groups of digits: with single quote, with underscore, or with hash - because "#" operator works with numbers as well as with symbol identifiers (and, unlike fasm 1, fasmg allows it anywhere, not only in lines generated by macros).

jmg wrote:

Tested this, and it also fixed an issue of not allowing > 8bit binary strings.
Now, only if the number overflows the field, does an error result = Good.

I think the problem must have been coming from elsewhere, since range checking in fasmg has not been changed recently or at any other time.

21 Sep 2016, 17:21

DOS386

Joined: 08 Dec 2006
Posts: 1900

DOS386 23 Sep 2016, 19:31

I've been using $FFFF'FFFF for years with FASM Smile

23 Sep 2016, 19:31

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