Lazarus
Home
Help
TinyPortal
Search
Login
Register
Lazarus
»
Forum
»
Free Pascal
»
General
(Moderators:
FPK
,
Tomas Hajny
) »
FPC compiles pusha/popa as a pushaw/popaw. Is it doing right?
Free Pascal
Website
Downloads
Wiki
Documentation
Bugtracker
Mailing List
Lazarus
Website
Downloads (Laz+FPC)
Packages (OPM)
FAQ
Wiki
Documentation (RTL/FCL/LCL)
Bugtracker
CCR Bugs
IRC channel
GIT
Mailing List
Other languages
Foundation
Website
Useful Wiki Links
Project Roadmap
Getting the Source
Screenshots
How to use the forum
About donations (wiki)
Bookstore
Computer Math and Games in Pascal
(preview)
Lazarus Handbook
Search
Advanced search
Recent
Making panels with lots o...
by
lainz
[
Today
at 04:00:20 pm]
Ribbon bar in Lazarus 3.2...
by
lainz
[
Today
at 03:58:42 pm]
A "leisure" question on W...
by
marcov
[
Today
at 03:49:31 pm]
Have anyone develop UEFI ...
by
PascalDragon
[
Today
at 02:16:40 pm]
Dynarray initialization p...
by
PascalDragon
[
Today
at 02:12:47 pm]
Program loop "runaway" wh...
by
Thaddy
[
Today
at 02:10:29 pm]
STARS and Regular POLYGON...
by
Boleeman
[
Today
at 02:05:38 pm]
how to change the color f...
by
cdbc
[
Today
at 12:02:27 pm]
Understanding and adjusti...
by
ArchChem
[
Today
at 11:49:35 am]
Offical launch of the 1 B...
by
abouchez
[
Today
at 11:14:35 am]
Free AI to use in local
by
Thaddy
[
Today
at 11:05:25 am]
Using KeyPress event, how...
by
KodeZwerg
[
Today
at 10:44:31 am]
Controlling the behavior ...
by
rvk
[
Today
at 08:31:48 am]
Big Numbers Math
by
Thaddy
[
Today
at 07:22:49 am]
Parquet?
by
Thaddy
[
Today
at 07:11:17 am]
Project fails on run but ...
by
jamie
[
Today
at 12:54:49 am]
Curling Pythagoras Tree: ...
by
Boleeman
[
Today
at 12:00:37 am]
how to search in rxmemory...
by
rcmz
[March 28, 2024, 10:19:54 pm]
Configure JCF messages
by
GordonFindlay
[March 28, 2024, 10:16:19 pm]
Poll: Watches and Display...
by
Martin_fr
[March 28, 2024, 10:15:08 pm]
Dialog ShowModal and an i...
by
d7_2_laz
[March 28, 2024, 09:51:39 pm]
JEDI error but unit compi...
by
Thaddy
[March 28, 2024, 09:30:33 pm]
Zeos components. Had to c...
by
Fantablup
[March 28, 2024, 04:17:13 pm]
[SOLVED] Completion box s...
by
furious programming
[March 28, 2024, 04:12:26 pm]
[LAMW] How to create a ca...
by
af0815
[March 28, 2024, 03:48:16 pm]
« previous
next »
Print
Pages: [
1
]
Author
Topic: FPC compiles pusha/popa as a pushaw/popaw. Is it doing right? (Read 975 times)
Avinash
Full Member
Posts: 117
FPC compiles pusha/popa as a pushaw/popaw. Is it doing right?
«
on:
June 05, 2021, 01:11:24 pm »
I would expect PUSHAD/POPAD from 32-bit compiler.
Logged
marcov
Administrator
Hero Member
Posts: 11384
FPC developer.
Re: FPC compiles pusha/popa as a pushaw/popaw. Is it doing right?
«
Reply #1 on:
June 05, 2021, 02:34:52 pm »
They have the same opcode, so the meaning is probably set by the mode ? That might be the disassembler at fault. (or whatever the backend assembler accepts, in the case of -a)
Logged
Avinash
Full Member
Posts: 117
Re: FPC compiles pusha/popa as a pushaw/popaw. Is it doing right?
«
Reply #2 on:
June 05, 2021, 03:51:48 pm »
Code: Pascal
[Select]
[+]
[-]
{$mode objfpc}
{$asmmode intel}
var
L
:
LongInt
;
begin
asm
xor
eax
,
eax
//pusha
dec eax
//popa
mov L
,
eax
end
;
WriteLn
(
HexStr
(
L
,
8
)
)
;
end
.
FFFFFFFF
Code: Pascal
[Select]
[+]
[-]
{$mode objfpc}
{$asmmode intel}
var
L
:
LongInt
;
begin
asm
xor
eax
,
eax
pusha
dec eax
popa
mov L
,
eax
end
;
WriteLn
(
HexStr
(
L
,
8
)
)
;
end
.
FFFF0000
Logged
PascalDragon
Hero Member
Posts: 5448
Compiler Developer
Re: FPC compiles pusha/popa as a pushaw/popaw. Is it doing right?
«
Reply #3 on:
June 05, 2021, 04:56:08 pm »
Yes, this is by design. See this comment from the compiler's source:
Code: Pascal
[Select]
[+]
[-]
{ pushf/popf/pusha/popa have to default to 16 bit in Intel mode
(Intel manual and Delphi-compatbile) -- setting the opsize for
these instructions doesn't change anything in the internal assember,
so change the opcode }
Logged
Print
Pages: [
1
]
« previous
next »
Lazarus
»
Forum
»
Free Pascal
»
General
(Moderators:
FPK
,
Tomas Hajny
) »
FPC compiles pusha/popa as a pushaw/popaw. Is it doing right?
TinyPortal
© 2005-2018