rp2040

commit 9d718a58506b90b4c12c30003fe4614faa5b3fe5
parent d4403ac482871dfe027adf4ad97af6e38f6edd86
Author: Matsuda Kenji <info@mtkn.jp>
Date:   Thu, 13 Apr 2023 09:39:42 +0900

main.c doesn't work for some reason.
compiled file contains
	add r7, sp, #0.
without this single line, it works.

Diffstat:
M
Makefile
 | 
4
++--
M
mach.s
 | 
20
+++++++++-----------
A
main.s
 | 
10
++++++++++

3 files changed, 21 insertions(+), 13 deletions(-)
diff --git a/Makefile b/Makefile
@@ -19,8 +19,8 @@ clean:
 boot2.o: boot2.s
 	$(AS) $(ASFLAGS) -o boot2.o boot2.s
 
-main.o: main.c
-	$(CC) $(CFLAGS) -o main.o main.c
+main.o: main.s
+	$(CC) $(CFLAGS) -o main.o main.s
 
 mach.o: mach.s
 	$(AS) $(ASFLAGS) -o mach.o mach.s
diff --git a/mach.s b/mach.s
@@ -9,11 +9,6 @@ vectors:
 	.section .text
 	.thumb_func
 reset:
-/*
-	ldr r0, sram_base
-	ldr r0, [r0, #0] // initial SP
-	mov sp, r0
-*/
 	bl main
 hang:
 	b hang
@@ -162,8 +157,7 @@ flash_read:
 	bl wait_ssi
 	bl ssi_pop
 
-	bl led_p0
-
+	ldr r3, xip_ssi_base
 	mov r1, #0x03
 	lsl r1, r1, #24
 	mov r2, #1
@@ -173,7 +167,10 @@ flash_read:
 	bl wait_ssi
 	bl ssi_pop
 
+	pop {pc}
+
 wait_ssi:
+	ldr r3, xip_ssi_base
 	ldr r1, [r3, #0x28] // SSI: SR
 	mov r2, #4 // TFE
 	tst r1, r2
@@ -184,19 +181,20 @@ wait_ssi:
 	bx lr
 
 ssi_pop:
-	push {lr}
+	push {r4, lr}
+	ldr r4, xip_ssi_base
 ssi_pop_loop:
-	ldr r1, [r3, #0x28] // SSI: SR
+	ldr r1, [r4, #0x28] // SSI: SR
 	mov r2, #8 // RFNE
 	tst r1, r2
 	beq ssi_empty
-	ldr r0, [r3, #0x60] // SSI: DR0
+	ldr r0, [r4, #0x60] // SSI: DR0
 	bl printh
 	mov r0, #'\n'
 	bl putchar
 	b ssi_pop_loop
 ssi_empty:
-	pop {pc}
+	pop {r4, pc}
 
 unreset:
 	// unreset subsystems specified by r0
diff --git a/main.s b/main.s
@@ -0,0 +1,10 @@
+	.global main
+main:
+	push {r7, lr}
+	//add r7, sp, #0
+	bl init
+loop:
+	bl led_p2
+	bl led_p2
+	bl led_p2
+	b loop