tkt

SCR2.1/ARM/TP16/printHW.s

@@ -0,0 +1,24 @@
+/*
+Lines enclosed here are comments
+A small program: prints "Hello World!"
+*/
+// From // to the end of this line is a comment: next are directives to the assembler
+.equ SYS_EXIT, 93
+.equ SYS_WRITE, 64
+.data // tells assembler to assemble the following in the data section
+msg: .asciz "Hello World!\n" //msg retains the address of the string
+.text // tells assembler to assemble the following
+// in the text (code) section
+.globl _start // _start is there where the program starts,
+// .globl makes it visible to the linker
+_start:
+mov x0,#1 // value 1 is placed in register x0
+adr x1,msg // the address retained by label msg is placed in register x1
+mov x2,#13
+mov w8, #SYS_WRITE // svc must find the syscall number in w8
+// and the syscall arguments in x0,x1,x2
+svc #0 // invoke syscall: displays on the screen
+mov x0, #0 // in x0 put the value you want to exit with
+mov w8,#SYS_EXIT
+svc #0
+.end