diff options
Diffstat (limited to 'newlib/libc/sys/sparc64/crt0.S')
| -rw-r--r-- | newlib/libc/sys/sparc64/crt0.S | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/newlib/libc/sys/sparc64/crt0.S b/newlib/libc/sys/sparc64/crt0.S new file mode 100644 index 00000000000..ed2cb7e9365 --- /dev/null +++ b/newlib/libc/sys/sparc64/crt0.S @@ -0,0 +1,123 @@ +! C run time start off + +! This file supports: +! +! - both 32bit pointer and 64bit pointer environments (at compile time) +! - an imposed stack bias (of 2047) (at run time) +! - medium/low and medium/anywhere code models (at run time) + +! Initial stack setup: +! +! bottom of stack (higher memory address) +! ... +! text of environment strings +! text of argument strings +! envp[envc] = 0 (4/8 bytes) +! ... +! env[0] (4/8 bytes) +! argv[argc] = 0 (4/8 bytes) +! ... +! argv[0] (4/8 bytes) +! argc (4/8 bytes) +! register save area (64 bits by 16 registers = 128 bytes) +! top of stack (%sp) + +! Stack Bias: +! +! It is the responsibility of the o/s to set this up. +! We handle both a 0 and 2047 value for the stack bias. + +! Medium/Anywhere code model support: +! +! In this model %g4 points to the start of the data segment. +! The text segment can go anywhere, but %g4 points to the *data* segment. +! It is up to the compiler/linker to get this right. +! +! Since this model is statically linked the start of the data segment +! is known at link time. Eg: +! +! sethi %hh(data_start), %g1 +! sethi %lm(data_start), %g4 +! or %g1, %hm(data_start), %g1 +! or %g4, %lo(data_start), %g4 +! sllx %g1, 32, %g1 +! or %g4, %g1, %g4 +! +! FIXME: For now we just assume 0. + +! FIXME: if %g1 contains a non-zero value, atexit() should be invoked +! with this value. + +#include <sys/syscallasm.h> + + TEXT_SECTION + ALIGN (4) + GLOBAL (ASM_PRIVATE_SYMBOL (start)) +ASM_PRIVATE_SYMBOL (start): + clr %fp + +! We use %g4 even if the code model is Medium/Low (simplifies the code). + + clr %g4 ! Medium/Anywhere base reg + +! If there is a stack bias in effect, account for it in %g5. Then always +! add %g5 to stack references below. This way the code can be used with +! or without an imposed bias. + + andcc %sp, 1, %g5 + bnz,a .LHaveBias + mov 2047, %g5 +.LHaveBias: + add %sp, %g5, %sp + +#if TARGET_PTR_SIZE == 32 + ! FIXME: We apparently assume here that there is no reserved word. + ! This is probably correct, but try to verify it. + ld [%sp + 0x80], %o0 ! argc + add %sp, 0x84, %o1 ! argv + add %o0, 1, %o2 + sll %o2, 2, %o2 +#else /* TARGET_PTR_SIZE == 64 */ + ld [%sp + 0x8c], %o0 ! argc.lo + add %sp, 0x90, %o1 ! argv + add %o0, 1, %o2 + sll %o2, 3, %o2 +#endif + add %o1, %o2, %o2 ! envp + sethi %hi (ASM_SYMBOL (environ)), %o3 + or %o3, %lo (ASM_SYMBOL (environ)), %o3 +#if TARGET_PTR_SIZE == 32 + st %o2, [%o3 + %g4] +#else /* TARGET_PTR_SIZE == 64 */ + stx %o2, [%o3 + %g4] +#endif + +! Restore any stack bias before we call main() ... + + sub %sp, %g5, %sp + + GLOBAL (ASM_SYMBOL (main)) + call ASM_SYMBOL (main) + +! FIXME: Not sure if this is needed anymore. +#if TARGET_PTR_SIZE == 32 + sub %sp, 0x20, %sp ! room to push args +#else /* TARGET_PTR_SIZE == 64 */ + sub %sp, 0x30, %sp ! room to push args +#endif + + GLOBAL (ASM_SYMBOL (exit)) + call ASM_SYMBOL (exit) + nop + + GLOBAL (ASM_SYMBOL (_exit)) + call ASM_SYMBOL (_exit) + nop + + set SYS_exit, %g1 + ta SYSCALL_TRAP ! in case user redefines __exit + +! If all the above methods fail to terminate the program, try an illegal insn. +! If that does not work, the o/s is hosed more than we are. + + WORD (0) |