From 50392995d6e7f3a10fb74bb2f9073a4790f8933c Mon Sep 17 00:00:00 2001
From: Jon Santmyer <jon@jonsantmyer.com>
Date: Mon, 11 Mar 2024 21:40:28 -0400
Subject: simple env with basic test init program

---
 lib/crt/Makefile        |  8 ++++++++
 lib/crt/x86_64/crt0.s   | 22 ++++++++++++++++++++++
 lib/crt/x86_64/crti.s   | 11 +++++++++++
 lib/crt/x86_64/crtn.s   |  7 +++++++
 lib/jlibc/Makefile      | 12 ++++++++++++
 lib/jlibc/stdlib/exit.c |  5 +++++
 6 files changed, 65 insertions(+)
 create mode 100644 lib/crt/Makefile
 create mode 100644 lib/crt/x86_64/crt0.s
 create mode 100644 lib/crt/x86_64/crti.s
 create mode 100644 lib/crt/x86_64/crtn.s
 create mode 100644 lib/jlibc/Makefile
 create mode 100644 lib/jlibc/stdlib/exit.c

(limited to 'lib')

diff --git a/lib/crt/Makefile b/lib/crt/Makefile
new file mode 100644
index 0000000..8b809fa
--- /dev/null
+++ b/lib/crt/Makefile
@@ -0,0 +1,8 @@
+SFILES := $(wildcard $(TARGET_MACHINE)/*.s)
+OFILES := $(patsubst %.s,%.o,$(SFILES))
+
+all: ${OFILES}
+	cp ${OFILES} $(LIBDIR)/
+
+%.o:%.s
+	$(AS) $< -o $@
diff --git a/lib/crt/x86_64/crt0.s b/lib/crt/x86_64/crt0.s
new file mode 100644
index 0000000..c5a0ba9
--- /dev/null
+++ b/lib/crt/x86_64/crt0.s
@@ -0,0 +1,22 @@
+.section .text
+.global _start
+_start:
+    #Setup start of stack frame
+    xorq %rbp, %rbp
+    pushq %rbp
+    pushq %rbp
+    movq %rsp, %rbp
+
+    #Save arguments passed to main
+    pushq %rdi
+    pushq %rsi
+
+    #Setup libc and call global constructors
+
+    #Call main
+    call main
+
+    #Exit
+    movq %rax, %rdi
+    call exit
+.size _start, . - _start
diff --git a/lib/crt/x86_64/crti.s b/lib/crt/x86_64/crti.s
new file mode 100644
index 0000000..0f06273
--- /dev/null
+++ b/lib/crt/x86_64/crti.s
@@ -0,0 +1,11 @@
+.section .init
+.global _init
+_init:
+    pushq %rbp
+    movq %rsp, %rbp
+
+.section .fini
+.global _fini
+_fini:
+    pushq %rbp
+    movq %rsp, %rbp
diff --git a/lib/crt/x86_64/crtn.s b/lib/crt/x86_64/crtn.s
new file mode 100644
index 0000000..9e31c23
--- /dev/null
+++ b/lib/crt/x86_64/crtn.s
@@ -0,0 +1,7 @@
+.section .init
+    popq %rbp
+    ret
+
+.section .fini
+    popq %rbp
+    ret
diff --git a/lib/jlibc/Makefile b/lib/jlibc/Makefile
new file mode 100644
index 0000000..65e645c
--- /dev/null
+++ b/lib/jlibc/Makefile
@@ -0,0 +1,12 @@
+CFILES := $(wildcard *.c)
+CFILES += $(wildcard */*.c)
+
+OFILES := $(patsubst %.c,%.o,$(CFILES))
+
+all: $(OUT)
+
+$(OUT): ${OFILES}
+	ar rcs $@ ${OFILES}
+
+%.o:%.c
+	$(CC) $(CFLAGS) -c $< -o $@
diff --git a/lib/jlibc/stdlib/exit.c b/lib/jlibc/stdlib/exit.c
new file mode 100644
index 0000000..225f74e
--- /dev/null
+++ b/lib/jlibc/stdlib/exit.c
@@ -0,0 +1,5 @@
+__attribute__((noreturn))
+void exit(int status)
+{
+    
+}
-- 
cgit v1.2.1