PlatformIO Community

How does platformio Link -DUSE_FLOATS=1

PlatformIO IDE
#1

hello, everyone
I want to print floating points in STC8 ,but I don t know how to correctly add the compilation flag “-DUSE_FLOATS=1”.
my platfromio.ini is list as follow:

[env:STC8H8K64U]
platform = intel_mcs51
board = STC8H8K64U
build_flags =
-DUSE_FLOATS=1

After doing this, I use the sprintf function, and still can only print “NO FLOAT”.
please help me and think very much.

#2 
build_flags =
   -DUSE_FLOATS=1

or

build_flags = -DUSE_FLOATS=1

would be correct.

Where however did you read that that would solve the problem?

With what code does what exact error occur?

#3

The official SDCC manual is as follows

printf() The default printf() implementation in printf_large.c does not support float (except on
ds390), only <NO FLOAT> will be printed instead of the value. To enable floating point output, recompile it
with the option -DUSE_FLOATS=1 on the command line. Use --model-large for the mcs51 port, since this uses a
lot of memory. To enable float support for the pic16 targets, see 4.7.9.

I don t know how to correctly add the compilation flag

#4

I tried this, but it couldn’t

#5

And with

build_flags =  --model-large -DUSE_FLOATS=1

?

#6 
I used the "- -model-large"
#7

Maybe I should send you the complete one

[env:STC8H8K64U]
platform = intel_mcs51
board = STC8A8K64D4

build_flags =
    -DUSE_FLOATS=1
	--model-large

extra_scripts = link_large.py


; upload_speed = 1152000

; change microcontroller
board_build.mcu = stc8a8k64d4

; change MCU frequency
board_build.f_cpu = 24000000L
#8

link_large.py

Import("env")
env.Append(LINKFLAGS=["--model-large"])
#9

Yes that looks good, I also devised the same solution. But it still won’t print these floats?

#10

I read that on the SDCC 4.2.3 manual (http://sdcc.sourceforge.net/doc/sdccman.pdf) that is indeed what one is supposed to do.

PlatformIO uses SDCC 4.2.0. This should be recent enough…

#11

If you want to test it out, download the latest tool chain version from Small Device C Compiler - Browse Files at SourceForge.net, install it locally then copy the toolchain files in C:\Users\<user>\.platformio\packages\toolchain-sdcc. So you can test that with 4.2.3.

#12

The current website seems to be only 4.2.0. Where did you find 4.2.3?

#13

Mhmm the documentation I linked to says 4.2.3, I think that is autogenerated. Let’s try the latest snapshot (for windows at Small Device C Compiler - Browse /snapshot_builds/x86_64-w64-mingw32 at SourceForge.net)