124 lines
3.0 KiB
ArmAsm
124 lines
3.0 KiB
ArmAsm
|
! 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)
|