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please help building proper libgcc
- From: Wojciech Puchar <wojtek at puchar dot net>
- To: gcc-help at gcc dot gnu dot org
- Date: Thu, 31 Jan 2019 10:31:33 +0100 (CET)
- Subject: please help building proper libgcc
i'm writing program for STM32L4 series MCU. It's cortex M4F
I don't use any "industry standard" software layers, want my program to
run from first instruction.
For now i compile programs with
arm-none-eabi-gcc -mfloat-abi=soft -mno-long-calls -mno-apcs-frame -ffreestanding -mcpu=cortex-m4 -mthumb -Os -Wno-multichar
And it works fine.when gcc needs it's own libraries (eg. handling
long long types) it needs thumb2 libraries
i link it with
arm-none-eabi-ld -L/usr/local/arm-gcc/lib/gcc/arm-none-eabi/4.9.0/thumb/thumb2 -nostdlib
with -lgcc after object files.
Links fine, works fine.
BUT this MCU have FPU. when i enable using it by
gcc -mfloat-abi=hard -mfpu=fpv4-sp-d16 -mno-long-calls -mno-apcs-frame -ffreestanding -mcpu=cortex-m4 -mthumb -Os -Wno-multichar
program don't link as there is incompatible ABI between objects and
when i tried /usr/local/arm-gcc/lib/gcc/arm-none-eabi/4.9.0/fpu directory
program links but doesn't work because this libgcc using 32-bit arm, not
There is no libgcc with thumb2 and hard float.
How to compile libgcc. Preferably with same compile options as my program.
Sorry i have no knowledge about building libgcc. please help