About irps reg,reglist {reverse pop reg}

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hopcode

Joined: 04 Mar 2008
Posts: 563
Location: Germany

hopcode 06 Feb 2010, 23:44

Hallo,
bug ?

Code:

format PE64 GUI 5.0
entry start
include 'win64a.inc'

define reglist rax rbx rdi rsi

section '.data' data readable writeable
  _title TCHAR 'Win64 program template',0
section '.code' code readable executable
start:
 irps reg,rax rbx rdi rsi {forward push reg} ;OK
 nop
 irps reg,rax rbx rdi rsi {reverse pop reg} ;OK
 nop
 irps reg,reglist {forward push reg} ;OK
 nop
 irps reg,reglist {reverse pop reg} ;<------ NOT OK
 ret

Cheers,
hopcode

06 Feb 2010, 23:44

LocoDelAssembly
Your code has a bug

Joined: 06 May 2005
Posts: 4624
Location: Argentina

LocoDelAssembly 07 Feb 2010, 00:35

hopcode, no, not a bug.

Check the difference between:

Code:

 irps reg,reglist {forward display `reg, 13 ,10}
 display "-------", 13, 10
 nop
 irps reg,reglist {reverse display `reg, 13 ,10}

And:

Code:

 match reglist, reglist{
 irps reg,reglist \{forward display \`reg, 13 ,10\}
 display "-------", 13, 10
 nop
 irps reg,reglist \{reverse display \`reg, 13 ,10\} 
 }

Your first "irps reg, reglist" gave you the illusion that it was working because PUSH and POP supports an arbitrary number of parameters (not separated by commas), and are always processed in forward order.

07 Feb 2010, 00:35

hopcode

Joined: 04 Mar 2008
Posts: 563
Location: Germany

hopcode 07 Feb 2010, 01:19

Oh, yes, lot of thanks.
That is a very subtle difference! To try an explanation: un-wrap/extract with a match the single elements contained under the symbol "reglist" and give them, as they are positioned, to the irps directive.
corrected to

Code:

define reglist rax rbx rdi rsi
match reglist, reglist{
 irps reg,reglist \{forward push reg \}
 irps reg,reglist \{reverse pop reg \} 
 }

Cheers,
hopcode

(moderator can freely move the tread if needed)

btw: i needed it for this thread where i will post a reply in 10 minutes
http://board.flatassembler.net/topic.php?p=109427#109427

07 Feb 2010, 01:19

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