commit 8814a540561ad066ba6155aeaccae86900bac2a8
parent fffa152122240112565655f51547ef6c5a6c0a57
Author: Matsuda Kenji <info@mtkn.jp>
Date: Fri, 8 Mar 2024 14:26:06 +0900
wip
Diffstat:
4 files changed, 30 insertions(+), 2 deletions(-)
diff --git a/ex3/main.c b/ex3/main.c
@@ -3,7 +3,7 @@ int puts(char *);
void printh(void *);
void set_alarm(unsigned int);
-extern void *proc0;
+extern void proc0_start, proc0_size;
// A proc represents a process in execution.
typedef struct proc {
@@ -31,6 +31,16 @@ main(void) {
proc *p0 = (proc *) 0x20041000, *p1 = (proc *) 0x20041100; // sram5
+ printh(&proc0_start);
+ puts("a");
+ printh(&proc0_size);
+ puts("b");
+
+ memcpy((void *)0x20000000, (void *)&proc0_start, (long) &proc0_size);
+ proc0();
+
+ puts("c");
+
p0->r[13] = (void *) 0x20000100; // sp
p0->r[14] = (void *) 0xdeadbeef; // lr
p0->r[15] = (void *) 0x20000000; // pc
diff --git a/ex3/memmap.ld b/ex3/memmap.ld
@@ -28,6 +28,8 @@ SECTIONS
.proc0 0x20000000 : {
*(.proc0)
} > SRAM AT > FLASH
+ proc0_start = LOADADDR(.proc0);
+ proc0_size = SIZEOF(.proc0);
.proc1 0x20000100 : {
*(.proc1)
} > SRAM AT > FLASH
diff --git a/ex3/proc.s b/ex3/proc.s
@@ -3,7 +3,7 @@
proc0:
ldr r0, msg0
bl puts
- b proc0
+ bx lr
msg0:
.asciz "proc0"
diff --git a/ex3/start.s b/ex3/start.s
@@ -234,6 +234,22 @@ puts_end:
mov r0, #0 // return value
pop {r4, pc}
+ // void *memcpy(void *s1, void *s2, long n);
+ // Memcpy copies n bytes from memory area s2 to s1. It returns s1.
+ // TODO: Use ldr instead of ldrb.
+ .global memcpy
+memcpy:
+ push {r4, lr}
+ mov r4, #0
+memcpy_loop:
+ ldrb r3, [r1, r4]
+ strb r3, [r0, r4]
+ add r4, #1
+ cmp r4, r2
+ blt memcpy_loop
+ pop {r4, pc}
+
+
putbyte:
ldr r3, uart0_base
mov r1, #1
