From: Robin Krens <robin@robinkrens.nl>
Date: Mon, 8 Jul 2019 13:39:02 +0000 (+0800)
Subject: jump to c
X-Git-Url: https://robinkrens.nl/gitweb/?a=commitdiff_plain;h=0c7ff283cb17c203da9a98fbd82ed87aa75abe52;p=cortex-from-scratch

jump to c
---

diff --git a/Makefile b/Makefile
index 2563e88..143f75d 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-CC=$(TOOLROOT)/arm-none-eabi-gcc
+CC=arm-none-eabi-gcc
 LD=arm-none-eabi-ld
 AR=$(TOOLROOT)/arm-none-eabi-ar
 AS=arm-none-eabi-as
@@ -12,7 +12,8 @@ as:
 
 all:
 	$(AS) $(CFLAGS) -o start.o start.asm
-	$(LD) -T link.ld -o start.out start.o
+	$(CC) $(CFLAGS) -c -o main.o main.c
+	$(LD) -nostartfiles -T link.ld -o start.out start.o main.o
 	$(MKIMG) -Obinary -R .data start.out kernel.bin
 
 run:
diff --git a/link.ld b/link.ld
index 903f1f5..5791784 100644
--- a/link.ld
+++ b/link.ld
@@ -4,7 +4,7 @@ MEMORY
 	SRAM (xrw) : ORIGIN = 0x20000000, LENGTH = 64K
 }
 
-ENTRY(_start)
+ENTRY(_start) 
 
 SECTIONS
 {
diff --git a/main.c b/main.c
new file mode 100644
index 0000000..57a199e
--- /dev/null
+++ b/main.c
@@ -0,0 +1,7 @@
+void main(void);
+
+void main(void ) {
+
+	int i = 1;
+	for (;;);
+}
diff --git a/start.asm b/start.asm
index 8af6fea..3c92e9b 100644
--- a/start.asm
+++ b/start.asm
@@ -9,23 +9,11 @@ _start:
 
 /* Start of main program */
 start:
-	movs r0, #5
-	movs r1, #1
-loop:
-	adds r1, r0
-	subs r0, #1
-	bne loop
-	/* Result is now in R1 */
-	ldr r0, =Result
-	str r1, [r0] 
-
-deadloop:
-	b deadloop
+	b main
+	b start
 
 	.data
-	.word 0 /* add two words*/
-	.word 0 
 Result:
-	.word 0 /* results now is in 0x20000008 (0x20000000 + 2 w) */
+	.word 'X' /* results now is in 0x20000008 (0x20000000 + 2 w) */
 	.end