Set stack pointers for each cpu in leon3mp

gistfile1.asm

!! Instructions for adding assembly code for leon3mp to setup stack pointers for each available CPU.

!! Running sparc-elf-gcc includes some system files in the final elf file, but editing these it is possible to set the stack pointer for each CPU before main is entered.

!! Edit the file sparc-elf-*.*.*/src/libgloss/sparc_leon/crt0.s
!! Add in the following assembly beneath the _start: label

        ! added code for setting stack pointer for each cpu
        rd %asr17, %g5			! load in configuration reg into g5
        srl %g5, 28, %g5 		! shift so only cpuid is seen
        sethi %hi(-1048576), %g1	! set the value -1MiB into register g1
        smul %g5, %g1, %g1		! multiply cpuid with required stack size
        save %sp, %g1, %sp 		! offset stack pointer by (cpuid * -1MebiByte)
        ! /added code for setting stack pointer for each cpu

!! This file can then be assembled:
!! ./sparc-elf-*.*.*/bin/../lib/gcc/sparc-elf/*.*.*/../../../../sparc-elf/bin/as -v -V -Qy -s -o crt0.o crt0.S

!! And copied into the library directory: (probably best to make a copy of the crt0.o file before hand)
!! sparc-elf-*.*.*/spark-elf/lib/

!! Now when compiling with sparc-elf-gcc this object file is included and each CPU is given a 1MebiByte stack.