diff options
| -rw-r--r-- | libc/sysdeps/linux/arm/crt1.S | 82 |
1 files changed, 70 insertions, 12 deletions
diff --git a/libc/sysdeps/linux/arm/crt1.S b/libc/sysdeps/linux/arm/crt1.S index 8ae897c06..86d6036d8 100644 --- a/libc/sysdeps/linux/arm/crt1.S +++ b/libc/sysdeps/linux/arm/crt1.S @@ -40,16 +40,48 @@ ... NULL */ +/* + For uClinux it looks like this: + + argc argument counter (integer) + argv char *argv[] + envp char *envp[] + argv[0] program name (pointer) + argv[1...N] program args (pointers) + argv[argc-1] end of args (integer) + NULL + env[0...N] environment variables (pointers) + NULL + +ARM register quick reference: + + Name Number ARM Procedure Calling Standard Role + + a1 r0 argument 1 / integer result / scratch register / argc + a2 r1 argument 2 / scratch register / argv + a3 r2 argument 3 / scratch register / envp + a4 r3 argument 4 / scratch register + v1 r4 register variable + v2 r5 register variable + v3 r6 register variable + v4 r7 register variable + v5 r8 register variable + sb/v6 r9 static base / register variable + sl/v7 r10 stack limit / stack chunk handle / reg. variable + fp r11 frame pointer + ip r12 scratch register / new-sb in inter-link-unit calls + sp r13 lower end of current stack frame + lr r14 link address / scratch register + pc r15 program counter +*/ .text .globl _start .type _start,#function _start: - /* Fetch address of fini */ - ldr ip, =_fini - - /* Clear the frame pointer since this is the outermost frame. */ + /* Clear the frame pointer and link register since this is the outermost frame. */ mov fp, #0 + mov lr, #0 /* Pop argc off the stack and save a pointer to argv */ ldr a2, [sp], #4 @@ -61,20 +93,46 @@ _start: /* Push rtld_fini */ str a1, [sp, #-4]! - /* Set up the other arguments in registers */ - ldr a1, =main - ldr a4, =_init +#ifdef L_Scrt1 + ldr sl, .L_GOT +.L_GOT_OFF: + add sl, pc, sl + + ldr ip, .L_GOT+4 /* _fini */ + ldr a1, [sl, ip] + str a1, [sp, #-4]! /* Push _fini */ + ldr ip, .L_GOT+8 /* _init */ + ldr a4, [sl, ip] + + ldr ip, .L_GOT+12 /* main */ + ldr a1, [sl, ip] + + /* __uClibc_main (main, argc, argv, init, fini, rtld_fini, stack_end) */ + /* Let the libc call main and exit with its return code. */ + b __uClibc_main(PLT) +#else + /* Fetch address of fini */ + ldr ip, =_fini /* Push fini */ str ip, [sp, #-4]! - /* __uClibc_main (main, argc, argv, init, fini, rtld_fini, stack_end) */ + /* Set up the other arguments in registers */ + ldr a1, =main + ldr a4, =_init + /* __uClibc_main (main, argc, argv, init, fini, rtld_fini, stack_end) */ /* Let the libc call main and exit with its return code. */ - bl __uClibc_main - - /* should never get here....*/ - bl abort + b __uClibc_main +#endif + +#ifdef L_Scrt1 +.L_GOT: + .word _GLOBAL_OFFSET_TABLE_-(.L_GOT_OFF+8) + .word _fini(GOT) + .word _init(GOT) + .word main(GOT) +#endif /* Define a symbol for the first piece of initialized data. */ .data |