From 4be5ceeec644a14844f149557eb278d37194b5ca Mon Sep 17 00:00:00 2001
From: Aaron Lindsay <aaron@aclindsay.com>
Date: Mon, 3 Sep 2012 23:44:36 -0400
Subject: [PATCH] Initial commit

---
 Makefile            | 52 +++++++++++++++++++++++++++++++++++++++++++++
 boot/Makefile.inc   |  3 +++
 boot/start.s        | 17 +++++++++++++++
 kernel/Makefile.inc |  3 +++
 kernel/hello.c      | 23 ++++++++++++++++++++
 link.ld             |  9 ++++++++
 6 files changed, 107 insertions(+)
 create mode 100644 Makefile
 create mode 100644 boot/Makefile.inc
 create mode 100644 boot/start.s
 create mode 100644 kernel/Makefile.inc
 create mode 100644 kernel/hello.c
 create mode 100644 link.ld

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..2d05d21
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,52 @@
+# Aedrix root Makefile
+# Copyright (C) 2012 Aaron Lindsay <aaron@aclindsay.com>
+
+# Config options for the code itself (should be separated from the Makefile sometime)
+ARCH = arm
+
+# Config options concerning the build process itself
+VERBOSE = 0 # 1 shows all compiler flags, 0 shows cleaner output
+
+# Define the tools to be used
+TOOL_PREFIX = arm-elf-
+AS = $(TOOL_PREFIX)as
+CC = $(TOOL_PREFIX)gcc
+LD = $(TOOL_PREFIX)ld
+
+# Define the flags we'll need for our tools
+KCFLAGS = -Wall -Wextra -Werror -nostdlib -nostartfiles -ffreestanding -std=gnu99
+KLDFLAGS = -T link.ld
+
+KOBJS = 
+
+include boot/Makefile.inc
+include kernel/Makefile.inc
+
+all: aedrix-kernel
+#all: 
+#	@echo $(KOBJS)
+
+aedrix-kernel: $(KOBJS)
+	$(if $(VERBOSE:1=),@echo '     LD $@')
+	$(if $(VERBOSE:1=),@)$(LD) $(KLDFLAGS) -o $@ $(KOBJS)
+
+%.o: %.c
+	$(if $(VERBOSE:1=),@echo '     CC $@')
+	$(if $(VERBOSE:1=),@)$(CC) $(KCFLAGS) -c -o $@ $<
+
+# Assembly files without preprocessor directives
+%.o: %.s
+	$(if $(VERBOSE:1=),@echo '     AS $@')
+	$(if $(VERBOSE:1=),@)$(AS) -o $@ $<
+
+# Assembly files with preprocessor directives
+%.o: %.S
+	$(if $(VERBOSE:1=),@echo '     AS $@')
+	$(if $(VERBOSE:1=),@)$(AS) -o $@ $<
+
+.PHONY : clean
+clean:
+	@echo '  CLEAN *.o'
+	@rm -f $(KOBJS)
+	@echo '  CLEAN aedrix-kernel'
+	@rm -f aedrix-kernel
diff --git a/boot/Makefile.inc b/boot/Makefile.inc
new file mode 100644
index 0000000..d9df028
--- /dev/null
+++ b/boot/Makefile.inc
@@ -0,0 +1,3 @@
+BOOT_PREFIX = boot
+
+KOBJS += $(BOOT_PREFIX)/start.o
diff --git a/boot/start.s b/boot/start.s
new file mode 100644
index 0000000..018e1f3
--- /dev/null
+++ b/boot/start.s
@@ -0,0 +1,17 @@
+interrupt_vector_table:
+    b . @ Reset
+    b . 
+    b . @ SWI instruction
+    b . 
+    b .
+    b .
+    b .
+    b .
+
+.comm stack, 0x10000 @ Reserve 64k stack in the BSS
+_start:
+    .globl _start
+    ldr sp, =stack+0x10000 @ Set up the stack
+    bl main @ Jump to the main function
+1: 
+    b 1b @ Halt
diff --git a/kernel/Makefile.inc b/kernel/Makefile.inc
new file mode 100644
index 0000000..21907ad
--- /dev/null
+++ b/kernel/Makefile.inc
@@ -0,0 +1,3 @@
+KERNEL_PREFIX = kernel
+
+KOBJS += $(KERNEL_PREFIX)/hello.o
diff --git a/kernel/hello.c b/kernel/hello.c
new file mode 100644
index 0000000..694f5e1
--- /dev/null
+++ b/kernel/hello.c
@@ -0,0 +1,23 @@
+#define SERIAL_BASE 0x16000000
+#define SERIAL_FLAG_REGISTER 0x18
+#define SERIAL_BUFFER_FULL (1 << 5)
+ 
+void putc (char c)
+{
+    /* Wait until the serial buffer is empty */
+    while (*(volatile unsigned long*)(SERIAL_BASE + SERIAL_FLAG_REGISTER) 
+                                       & (SERIAL_BUFFER_FULL));
+    /* Put our character, c, into the serial buffer */
+    *(volatile unsigned long*)SERIAL_BASE = c;
+}
+ 
+void puts (const char * str)
+{
+    while (*str) putc (*str++);
+}
+ 
+int main (void)
+{
+    puts ("hello, world!\n");
+    return 0;
+}
diff --git a/link.ld b/link.ld
new file mode 100644
index 0000000..89f7549
--- /dev/null
+++ b/link.ld
@@ -0,0 +1,9 @@
+ENTRY (_start)
+
+SECTIONS
+{
+    . = 0;
+    .text : { *(.text*) *(.rodata*) }
+    .data : { *(.data*) }
+    .bss : { *(.bss*) *(COMMON*) }
+}