cpu/arm7_common: fix compilation with 12.2.0

[maribu]

Contribution description

This fixes:

Assembler messages:
Fatal error: unknown option `-ggdb'

Testing procedure

Run with a recent toolchain:

$ make BOARD=msba2 -C examples/hello-world/

With master

$ make BOARD=msba2 -C examples/hello-world/
make: Entering directory '/home/maribu/Repos/software/RIOT/examples/hello-world'
Building application "hello-world" for "msba2" with MCU "lpc23xx".

"make" -C /home/maribu/Repos/software/RIOT/boards/common/init
"make" -C /home/maribu/Repos/software/RIOT/boards/msba2
"make" -C /home/maribu/Repos/software/RIOT/core
"make" -C /home/maribu/Repos/software/RIOT/core/lib
"make" -C /home/maribu/Repos/software/RIOT/cpu/lpc23xx
Assembler messages:
Fatal error: unknown option `-ggdb'
make[2]: *** [/home/maribu/Repos/software/RIOT/Makefile.base:176: /home/maribu/Repos/software/RIOT/examples/hello-world/bin/msba2/cpu/asmfunc.o] Error 1
make[1]: *** [/home/maribu/Repos/software/RIOT/Makefile.base:31: ALL--/home/maribu/Repos/software/RIOT/cpu/lpc23xx] Error 2
make: *** [/home/maribu/Repos/software/RIOT/examples/hello-world/../../Makefile.include:738: application_hello-world.module] Error 2
make: Leaving directory '/home/maribu/Repos/software/RIOT/examples/hello-world'

This PR

$  make BOARD=msba2 -C examples/hello-world/
make: Entering directory '/home/maribu/Repos/software/RIOT/examples/hello-world'
Building application "hello-world" for "msba2" with MCU "lpc23xx".

"make" -C /home/maribu/Repos/software/RIOT/boards/common/init
"make" -C /home/maribu/Repos/software/RIOT/boards/msba2
"make" -C /home/maribu/Repos/software/RIOT/core
"make" -C /home/maribu/Repos/software/RIOT/core/lib
"make" -C /home/maribu/Repos/software/RIOT/cpu/lpc23xx
"make" -C /home/maribu/Repos/software/RIOT/cpu/arm7_common
"make" -C /home/maribu/Repos/software/RIOT/cpu/arm7_common/periph
"make" -C /home/maribu/Repos/software/RIOT/cpu/lpc23xx/periph
"make" -C /home/maribu/Repos/software/RIOT/drivers
"make" -C /home/maribu/Repos/software/RIOT/drivers/periph_common
"make" -C /home/maribu/Repos/software/RIOT/sys
"make" -C /home/maribu/Repos/software/RIOT/sys/auto_init
"make" -C /home/maribu/Repos/software/RIOT/sys/bitfield
"make" -C /home/maribu/Repos/software/RIOT/sys/div
"make" -C /home/maribu/Repos/software/RIOT/sys/malloc_thread_safe
"make" -C /home/maribu/Repos/software/RIOT/sys/newlib_syscalls_default
"make" -C /home/maribu/Repos/software/RIOT/sys/pm_layered
"make" -C /home/maribu/Repos/software/RIOT/sys/stdio_uart
   text	  data	   bss	   dec	   hex	filename
  12276	   128	  6932	 19336	  4b88	/home/maribu/Repos/software/RIOT/examples/hello-world/bin/msba2/hello-world.elf
make: Leaving directory '/home/maribu/Repos/software/RIOT/examples/hello-world'

Issues/PRs references

None

[maribu]

Thx :)

[benpicco]

It's strange that makefiles/arch/cortexm.inc.mk also has this with apparently no complaints.

(And yea, those flags are arch independent, some de-duplication would probably be a good idea…)

[maribu]

Sadly not, those are indeed to different ISAs. The ARM7 MCUs support the ARM ISA (and have incomplete support for the thumb ISA as well), the Cortex M MCUs do not support the ARM ISA anymore but have full support for the thumb ISA.

I tried to build the ARM7 stuff with -mthumb which mostly worked, but irq_disable() and irq_restore() require the mrs instruction, which only is available in later versions of the thumb ISA. Maybe there are implementations that would work with the early thumb as well. I think that thumb would be beneficial. On all MCUs code density would profit significantly, one MCUs with a 16 bit but the performance would benefit as well.

[benpicco]

I know, but I'm talking about

CFLAGS_LINK = -ffunction-sections -fdata-sections -fshort-enums
CFLAGS_DBG  ?= -ggdb -g3
CFLAGS_OPT  ?= -Os

CFLAGS      += $(CFLAGS_CPU) $(CFLAGS_LINK) $(CFLAGS_DBG) $(CFLAGS_OPT)
ASFLAGS     += $(CFLAGS_CPU) $(CFLAGS_DBG)
LINKFLAGS   += -T$(RIOTCPU)/$(CPU)/ldscripts/$(CPU).ld
LINKFLAGS   += $(CFLAGS_CPU) $(CFLAGS_DBG) $(CFLAGS_OPT) -static -lgcc -nostartfiles
LINKFLAGS   += -Wl,--gc-sections

This is completely arch independent and copy & pasted for each target