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-rw-r--r--libc/sysdeps/linux/arm/crt0.S26
-rw-r--r--libc/sysdeps/linux/arm/crt0pic.S67
2 files changed, 42 insertions, 51 deletions
diff --git a/libc/sysdeps/linux/arm/crt0.S b/libc/sysdeps/linux/arm/crt0.S
index 72a45a29f..3660f4167 100644
--- a/libc/sysdeps/linux/arm/crt0.S
+++ b/libc/sysdeps/linux/arm/crt0.S
@@ -3,6 +3,7 @@
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
@@ -40,18 +41,10 @@ This file now uses the register naming from the ARM Procedure Calling Standard
.global _start
.global exit
.global main
- .global __libc_init
- .global __init_stdio
- .global __stdio_close_all
- .global _void_void_null_func
.type _start,%function
.type exit,%function
.type main,%function
- .type __libc_init,%function
- .type __init_stdio,%function
- .type __stdio_close_all,%function
- .type _void_void_null_func,%function
.text
_start:
@@ -73,27 +66,12 @@ _start:
add a3, a3, #4
str a3, [a4, #0]
- /* Tell libc to initialize whatever it needs */
- bl __libc_init
- bl __init_stdio
bl main
bl exit
-_void_void_null_func:
- mov pc, lr
-
-.weak __libc_init
-__libc_init = _void_void_null_func
-
-.weak __init_stdio
-__init_stdio = _void_void_null_func
-
-.weak __stdio_close_all
-__stdio_close_all = _void_void_null_func
-
.align 2
.L3:
- .word environ
+ .word __environ
.data
diff --git a/libc/sysdeps/linux/arm/crt0pic.S b/libc/sysdeps/linux/arm/crt0pic.S
index a668ac31f..04b1cb755 100644
--- a/libc/sysdeps/linux/arm/crt0pic.S
+++ b/libc/sysdeps/linux/arm/crt0pic.S
@@ -1,21 +1,49 @@
+/* When we enter this piece of code, the program stack looks like this:
+ argc argument counter (integer)
+ 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
+
+ When we are done here, we want
+ a1=argc
+ a2=argv[0]
+ a3=argv[argc+1]
+
+ARM register quick reference:
+
+ Name Number APCS Role
+
+ a1 0 argument 1 / integer result / scratch register / argc
+ a2 1 argument 2 / scratch register / argv
+ a3 2 argument 3 / scratch register / envp
+ a4 3 argument 4 / scratch register
+ v1 4 register variable
+ v2 5 register variable
+ v3 6 register variable
+ v4 7 register variable
+ v5 8 register variable
+ sb/v6 9 static base / register variable
+ sl/v7 10 stack limit / stack chunk handle / reg. variable
+ fp 11 frame pointer
+ ip 12 scratch register / new-sb in inter-link-unit calls
+ sp 13 lower end of current stack frame
+ lr 14 link address / scratch register
+ pc 15 program counter
+*/
+
.text
.align 2
.global __environ
.global _start
.global exit
.global main
- .global __libc_init
- .global __init_stdio
- .global __stdio_close_all
- .global _void_void_null_func
.type _start,%function
.type exit,%function
.type main,%function
- .type __libc_init,%function
- .type __init_stdio,%function
- .type __stdio_close_all,%function
- .type _void_void_null_func,%function
@@ -23,21 +51,18 @@
@ r1 = argv
@ r2 = envp
@ sl = data segment
+#define BASEREG r9
.text
_start:
@ adjust the data segment base pointer
ldr r3,=__data_start
sub sl,sl,r3
- mov r9,sl
+ mov BASEREG,sl
ldr r3, .L3
- str r2,[r9,r3]
+ str r2,[BASEREG,r3]
- /* Tell libc to initialize whatever it needs */
- bl __libc_init
- bl __init_stdio
-
/* pull argc, argv and envp off the stack */
ldr r0,[sp, #0]
ldr r1,[sp, #4]
@@ -47,21 +72,9 @@ _start:
/* ldr r0,=0 */
bl exit
-_void_void_null_func:
- mov pc, lr
-
-.weak __libc_init
-__libc_init = _void_void_null_func
-
-.weak __init_stdio
-__init_stdio = _void_void_null_func
-
-.weak __stdio_close_all
-__stdio_close_all = _void_void_null_func
-
.align 2
.L3:
- .word environ
+ .word __environ
.data