rp2040

commit 3ae2e8a223fecd39b899e61c9ba6be0d6f9b5534
parent a33c6373643c843aa5cf61081cfc32ab296eae8e
Author: Matsuda Kenji <info@mtkn.jp>
Date:   Wed, 28 Feb 2024 08:50:17 +0900

add a function

Diffstat:
M
ex3/main.s
 | 
25
++++++++++++++++++-------

1 file changed, 18 insertions(+), 7 deletions(-)
diff --git a/ex3/main.s b/ex3/main.s
@@ -136,12 +136,8 @@ unreset_chk1:
 	bl set_alarm
 
 loop:
-	ldr r0, =0xdeadcafe
-	bl printh
-	mov r0, #'\r'
-	bl putbyte
-	mov r0, #'\n'
-	bl putbyte
+	ldr r0, =message
+	bl puts
 	wfi
 	b loop
 
@@ -229,6 +225,20 @@ alpha:
 	bge printh_loop
 	pop {r4, r5, r6, r7, pc}
 
+	// puts prints null terminated string starting at r0.
+puts:
+	push {r4, lr}
+	mov r4, r0
+puts_loop:
+	ldrb r0, [r4, #0]
+	cmp r0, #0
+	beq puts_end
+	bl putbyte
+	add r4, #1
+	b puts_loop
+puts_end:
+	pop {r4, pc}
+
 putbyte:
 	ldr r3, uart0_base
 	mov r1, #1
@@ -341,4 +351,5 @@ sio_base:
 	.word 0xd0000000
 ppb_base:
 	.word 0xe0000000
-
+message:
+	.asciz "Hello, World!\r\n"