From: Robin Krens <robin@robinkrens.nl>
Date: Fri, 5 Jul 2019 09:09:55 +0000 (+0800)
Subject: first commit, basic setup and makefile
X-Git-Url: https://robinkrens.nl/gitweb/?a=commitdiff_plain;h=fe0e1e676b1d1a3f151dbe8cdf7a54ec78e1723f;p=cortex-from-scratch

first commit, basic setup and makefile
---

fe0e1e676b1d1a3f151dbe8cdf7a54ec78e1723f
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..cc01e47
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,33 @@
+CC=$(TOOLROOT)/arm-none-eabi-gcc
+LD=arm-none-eabi-ld
+AR=$(TOOLROOT)/arm-none-eabi-ar
+AS=arm-none-eabi-as
+MKIMG=arm-none-eabi-objcopy
+
+LDFLAGS+= -mthumb -mcpu=cortex-m3 
+CFLAGS+= -mcpu=cortex-m3 -mthumb 
+
+as: 
+	$(AS) $(CFLAGS) -o start.o start.asm
+
+all:
+	$(AS) $(CFLAGS) -o start.o start.asm
+	$(LD) -T link.ld -o start.out start.o
+	$(MKIMG) -Obinary start.out kernel.bin
+
+run:
+	qemu-system-arm	-monitor stdio -M lm3s6965evb -kernel kernel.bin
+
+examine:
+	arm-none-eabi-objdump -S start.out
+
+%.o: %.c
+	$(CC) -c $(CFLAGS) $< -o $@
+	$(CC) -MM $(CFLAGS) $< > $*.d
+
+%.o: %.s
+	$(CC) -c $(CFLAGS) $< -o $@
+
+
+
+
diff --git a/link.ld b/link.ld
new file mode 100644
index 0000000..00ce90e
--- /dev/null
+++ b/link.ld
@@ -0,0 +1,21 @@
+MEMORY
+{
+	FLASH (rx) : ORIGIN = 0x00000000, LENGTH = 512K
+	SRAM (xrw) : ORIGIN = 0x20000000, LENGTH = 64K
+}
+
+ENTRY(_start)
+
+SECTIONS
+{
+	.text : ALIGN(4)
+	{
+		/* (.vector_table */ 
+		*(.text)
+
+	} > FLASH
+	.data : 
+	{
+		*(.data)
+	} > SRAM
+}
diff --git a/start.asm b/start.asm
new file mode 100644
index 0000000..8991594
--- /dev/null
+++ b/start.asm
@@ -0,0 +1,22 @@
+	.equ STACK_TOP, 0x20000800
+	.text
+	.global _start
+	.code 16
+	.syntax unified
+_start:
+	.word STACK_TOP, start
+	.type start, function
+
+/* Start of main program */
+start:
+	movs r0, #10
+	movs r1, #5
+loop:
+	adds r1, r0
+	subs r0, #1
+	bne loop
+/* Result is now in R1 */
+deadloop:
+	b deadloop
+	.end
+