From 97d3551106495fa18969e2690720b621ba5a9c0b Mon Sep 17 00:00:00 2001
From: Jake Mannens <jake72360@gmail.com>
Date: Sun, 24 Jun 2018 02:27:22 +1000
Subject: Re-structured the source tree and modified makefiles accordingly.
 Hopefully further separation will help to keep the code readable and
 understandable.

---
 usrbin/Makefile | 32 ++++++++++++++++++++++++++++++++
 usrbin/lib.s    | 10 ++++++++++
 usrbin/link.ld  |  8 ++++++++
 usrbin/main.c   |  7 +++++++
 usrbin/print.c  |  3 +++
 5 files changed, 60 insertions(+)
 create mode 100644 usrbin/Makefile
 create mode 100644 usrbin/lib.s
 create mode 100644 usrbin/link.ld
 create mode 100644 usrbin/main.c
 create mode 100644 usrbin/print.c

(limited to 'usrbin')

diff --git a/usrbin/Makefile b/usrbin/Makefile
new file mode 100644
index 0000000..16a607f
--- /dev/null
+++ b/usrbin/Makefile
@@ -0,0 +1,32 @@
+TARGET = usrbin_blob.o
+
+SRCS = $(wildcard *.c)
+ASMS = $(wildcard *.s)
+OBJS = $(SRCS:.c=.o) $(ASMS:.s=.o)
+
+CFLAGS = -m32 -I../include -ffreestanding -nostdinc -nostdlib -fno-stack-protector -fno-pie
+LDFLAGS = -m elf_i386 -T link.ld
+ASMFLAGS = -f elf32
+
+CC = gcc $(CFLAGS)
+LD = ld $(LDFLAGS)
+ASM = nasm $(ASMFLAGS)
+
+all: build
+
+build: $(TARGET)
+
+.s.o:
+	$(ASM) -o $*.o $^
+
+.c.o:
+	$(CC) -c -o $*.o $^
+
+$(TARGET): $(OBJS)
+	$(LD) -o usrbin.bin $(OBJS)
+	objcopy -I binary -O elf32-i386 -B i386 usrbin.bin $(TARGET)
+
+clean:
+	rm -f usrbin.bin
+	rm -f $(OBJS)
+	rm -f $(TARGET)
diff --git a/usrbin/lib.s b/usrbin/lib.s
new file mode 100644
index 0000000..ffe4f5f
--- /dev/null
+++ b/usrbin/lib.s
@@ -0,0 +1,10 @@
+bits 32
+
+extern main
+
+section .entry
+init:
+  call main
+.loop:
+  ; loop forever
+  jmp .loop
diff --git a/usrbin/link.ld b/usrbin/link.ld
new file mode 100644
index 0000000..c1a7a42
--- /dev/null
+++ b/usrbin/link.ld
@@ -0,0 +1,8 @@
+OUTPUT_FORMAT(binary)
+SECTIONS
+{
+  . = 0x100000;
+  .text : { *(.entry); .*(.text) }
+  .data : { *(.data) }
+  .bss : { *(.bss) }
+}
diff --git a/usrbin/main.c b/usrbin/main.c
new file mode 100644
index 0000000..5cc7567
--- /dev/null
+++ b/usrbin/main.c
@@ -0,0 +1,7 @@
+#include <stdint.h>
+
+extern int print(char*);
+
+void main(void) {
+  print("We did it ma!\n");
+}
diff --git a/usrbin/print.c b/usrbin/print.c
new file mode 100644
index 0000000..ea32cdf
--- /dev/null
+++ b/usrbin/print.c
@@ -0,0 +1,3 @@
+#include <unistd.h>
+
+_syscall1(int, print, char*, s);
-- 
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