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-rw-r--r--tools/include/nolibc/arch-arm.h14
1 files changed, 10 insertions, 4 deletions
diff --git a/tools/include/nolibc/arch-arm.h b/tools/include/nolibc/arch-arm.h
index 875b21975137..e4ba77b0310f 100644
--- a/tools/include/nolibc/arch-arm.h
+++ b/tools/include/nolibc/arch-arm.h
@@ -180,10 +180,16 @@ void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) _start(void)
__asm__ volatile (
"pop {%r0}\n" // argc was in the stack
"mov %r1, %sp\n" // argv = sp
- "add %r2, %r1, %r0, lsl #2\n" // envp = argv + 4*argc ...
- "add %r2, %r2, $4\n" // ... + 4
- "and %r3, %r1, $-8\n" // AAPCS : sp must be 8-byte aligned in the
- "mov %sp, %r3\n" // callee, an bl doesn't push (lr=pc)
+
+ "add %r2, %r0, $1\n" // envp = (argc + 1) ...
+ "lsl %r2, %r2, $2\n" // * 4 ...
+ "add %r2, %r2, %r1\n" // + argv
+
+ "mov %r3, $8\n" // AAPCS : sp must be 8-byte aligned in the
+ "neg %r3, %r3\n" // callee, and bl doesn't push (lr=pc)
+ "and %r3, %r3, %r1\n" // so we do sp = r1(=sp) & r3(=-8);
+ "mov %sp, %r3\n" //
+
"bl main\n" // main() returns the status code, we'll exit with it.
"movs r7, $1\n" // NR_exit == 1
"svc $0x00\n"