Which bitness first ?

[Bart]

On Windows I mainly use 32-bit (because the compiler is natively 32 bit).
I only cross-compile to win64 if I see an advantage (or to check it compiles at all).
I maybe just too lazy to rebuild Lazarus to 64-bit and build all by default to 64-bit.
My hardware surely should not be a  problem.

Bart

[Scoops]

I only install 32 bit for now, in the readme file for 64bit windows download page its written.

The Lazarus team recommends to use the 32bit Version of Lazarus, even for working on 64bit platforms, or for generating 64 bit applications.

Is this advice still recommended or is it outdated ?

[Martin_fr]

I only install 32 bit for now, in the readme file for 64bit windows download page its written.

The Lazarus team recommends to use the 32bit Version of Lazarus, even for working on 64bit platforms, or for generating 64 bit applications.

Is this advice still recommended or is it outdated ?

https://sourceforge.net/projects/lazarus/files/Lazarus%20Windows%2064%20bits/Lazarus%203.4/
Where is that written?

I would say it is outdated.

Especially since the 32bit IDE version can debug 64bit apps only with gdb, but not with FpDebug. While the 64bit IDE can debug both bitnesses (with FpDebug).

[Martin_fr]

I found it. https://sourceforge.net/projects/lazarus/files/Lazarus%20Windows%2064%20bits/

It is outdated. That was SEH related. Only fpc 2.x.

[Thaddy]

And everybody still adheres to it since it still shows up everywhere without reason.
I have been cross compiling from 64 to 32 for many years against all advice to do it the other way around.

[Thaddy]

To everybody: let's fix this. It does not need code (well, fpcupdeluxe needs a warning to remove), just a couple of doc maintainers.

[marcov]

(FPC still has an issue afaik, when 64-bit to 32-bit cross-compilation on x86 doesn't yield the same results because the constants in the compiler are rounded differently (64 vs 80-bit I assume))

[Thaddy]

For a cross compiler that should never be an issue. Extended should end up as 80 bits.

[marcov]

For a cross compiler that should never be an issue. Extended should end up as 80 bits.

WIndows 64-bit doesn't have extended. So a 80-bit soft float need to be developed and valdiated.

[Thaddy]

Which is perfecrly possible with softfloat.... and that is supported. It is also possible with some Florian specific tricks on x86_86-win64.(this is hardly documented, but works)
It is developed.

[Martin_fr]

(FPC still has an issue afaik, when 64-bit to 32-bit cross-compilation on x86 doesn't yield the same results because the constants in the compiler are rounded differently (64 vs 80-bit I assume))

Maybe, but the add on on the lazarus download side, actually is a 32 bit ppc, marketed as cross compiler from 64 to 32 bit.

[madref]

I don't have a choice. I am on a Mac... so 64 it is

[Mr.Madguy]

Both. High level languages like Pascal or C++ can produce fully 32bit<->64bit portable code, if some simple rules are followed. It's not ASM. I usually create both 32bit and 64bit building configurations right when I create new project and then compile and test them both. It's actually good idea, because some memory access issues don't show up on one bitness, but do on other. For example 32bit code can work properly, but 64bit one wouldn't.

[VisualLab]

Is your question only about developing Windows/Linux on x86/AMD64? Or maybe it also covers 32-bit ARM microcontrollers (e.g. RPi Pico)?

The question is meant to cover CPUs and O/Ss that support both bitnesses, e.g, on Windows it is possible (given the right O/S version) to run either a 32 bit program or a 64 bit program.   Since both options are available, I wanted to know if programmers had a preference as to which version to develop first given those possibilities.

On my home computer (typical PC) running Winows 10 64-bit, I use Lazarus 64-bit. On 2 small computers for experiments I use:

• Up Squared (Intel Celeron, 4 GB RAM) - Windows 10 64-bit and Linux Kubuntu 23.04 64-bit are installed - Lazarus 64-bit is installed in both OSes,
• on Raspberry Pi 3B - Raspberry Pi OS Bullseye 32-bit - Lazarus 32-bit are installed.

On Raspberry Pi 3B I tried to use Raspberry Pi OS Bookworm 64-bit, but the OS is slow.

[PascalDragon]

Which is perfecrly possible with softfloat.... and that is supported. It is also possible with some Florian specific tricks on x86_86-win64.(this is hardly documented, but works)
It is developed.

Softfloat is still missing a few basic math routines like exp or ld that are necessary for complete coverage and thus consistent compilation from non-Extended targets to those that have Extended. Also the compiler currently does not support softfloat inside itself correctly, so it wouldn't work either currently.