Bugfix rpn_lib.asm

Frogot that rbx MUST be preserved :/

rpn_lib.asm

@@ -43,11 +43,13 @@ section .note.GNU-stack noalloc noexec nowrite progbits
 section .data
 
 rpn_exec:
-	; unsigned long int rpn_exec(unsigned long int stack_size, unsigned long args)
+	; unsigned long int rpn_exec(unsigned long int stack_size, unsigned long args, unsigned long int *stack)
 	; rdi -> stack size (in values (64 bits))
 	; rsi -> args pointers
-	
+	; rdx -> stack pointer or null
+
 	enter 32, 0
+	push rbx ; rbx MUST BE PRESERVED !!! (like r12 to r15 and rbp !)
 	
 	mov stack_size, rdi
 	mov args_ptr, rsi
@@ -102,6 +104,7 @@ rpn_exec_ret:
 	syscall
 	pop rax
 	.end:
+	pop rbx
 	leave
 	ret
 part_sz rpn_exec_ret