rp2040

commit aeaf4505ba3fc32b2d2bad04e468b6e43fd04eba
parent a41034b590794a16c2852ec2cd7bb04c51ec5869
Author: Matsuda Kenji <info@mtkn.jp>
Date:   Thu, 28 Mar 2024 07:48:04 +0900

save and restore context from and to the psp

Diffstat:
M
ex3/main.c
 | 
6
++++++
M
ex3/proc.s
 | 
21
+++++++++++----------

2 files changed, 17 insertions(+), 10 deletions(-)
diff --git a/ex3/main.c b/ex3/main.c
@@ -102,6 +102,12 @@ switch_context(unsigned int r[17]) {
 	ptab.tail = p;
 	ptab.tail->next = NULL;
 
+	puts("next context:");
+	for (int i = 0; i < 17; i++) {
+		printh(ptab.head->r[i]);
+		puts("");
+	}
+
 	return ptab.head->r;
 }
 
diff --git a/ex3/proc.s b/ex3/proc.s
@@ -4,6 +4,7 @@
 proc0:
 	ldr r0, =msg0
 	bl puts
+	ldr r0, =0xdeadbeef
 	wfi
 	b proc0
 
@@ -44,21 +45,21 @@ isr_alarm:
 	sub sp, sp, #(17*4) // unsigned int r[17];
 	mov r1, sp
 
-	mov r2, #(17*4 + 4) // +4 for pushed lr
+	mrs r2, psp
 	mov r3, #0
-	ldr r0, [r1, r2] // r0
+	ldr r0, [r2, #0] // r0
 	str r0, [r1, r3]
 	add r2, r2, #4
 	add r3, r3, #4
-	ldr r0, [r1, r2] // r1
+	ldr r0, [r2, #0] // r1
 	str r0, [r1, r3]
 	add r2, r2, #4
 	add r3, r3, #4
-	ldr r0, [r1, r2] // r2
+	ldr r0, [r2, #0] // r2
 	str r0, [r1, r3]
 	add r2, r2, #4
 	add r3, r3, #4
-	ldr r0, [r1, r2] // r3
+	ldr r0, [r2, #0] // r3
 	str r0, [r1, r3]
 
 	add r3, r3, #4
@@ -85,7 +86,7 @@ isr_alarm:
 
 	add r2, r2, #4
 	add r3, r3, #4
-	ldr r0, [r1, r2]
+	ldr r0, [r2, #0]
 	str r0, [r1, r3] // r12
 
 	add r3, r3, #4
@@ -94,23 +95,23 @@ isr_alarm:
 
 	add r2, r2, #4
 	add r3, r3, #4
-	ldr r0, [r1, r2]
+	ldr r0, [r2, #0]
 	str r0, [r1, r3] // lr
 
 	add r2, r2, #4
 	add r3, r3, #4
-	ldr r0, [r1, r2]
+	ldr r0, [r2, #0]
 	str r0, [r1, r3] // ReturnAddress(ExceptionType): The next pc at interrupt.
 
 	add r2, r2, #4
 	add r3, r3, #4
-	ldr r0, [r1, r2] // xpsr
+	ldr r0, [r2, #0] // xpsr
 	str r0, [r1, r3]
 
 	mov r0, r1
 	bl switch_context // r0 is the r[17] of the next task.
 	add sp, sp, #(17*4)
-	add r2, sp, #4 // for the popped lr
+	mrs r2, psp
 	ldr r1, [r0, #(0 * 4)] // r0
 	str r1, [r2, #0]
 	ldr r1, [r0, #(1 * 4)] // r1