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! 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 "syscallasm.h"
#ifndef TARGET_PTR_SIZE
#define TARGET_PTR_SIZE 32
#endif
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)
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