Add assembly start code for netbsd.

	Seems to work so far.

3 files changed, 129 insertions, 1 deletions

diff --git a/mk/c.mk b/mk/c.mk
index e75f1e2..81ff1fa 100644
--- a/mk/c.mk
+++ b/mk/c.mk
@@ -9,7 +9,7 @@ _LIBINCPATHS=$(addprefix -I, $(dir $(DEPS))) $(_PCHDRS)
 _LIBPATHS=$(addprefix -l, $(patsubst lib%.a,%,$(notdir $(DEPS)))) $(_PCLIBS)
 
 # yeah, I should probably remove -Werror, but it's nice for developing alone.
-CFLAGS += -Wall -Wextra -Werror -Wno-unused-parameter -Wno-missing-field-initializers -Wno-sign-compare -g -O0
+CFLAGS += -Wall -Wextra -Werror -Wno-unused-parameter -Wno-missing-field-initializers -Wno-sign-compare -Wno-char-subscripts -g -O0
 CFLAGS += -MMD -MP -MF .deps/$(subst /,-,$*).d
 
 LIB ?= $(INSTLIB)
diff --git a/rt/abort-netbsd.s b/rt/abort-netbsd.s
new file mode 100644
index 0000000..a4b12bb
--- /dev/null
+++ b/rt/abort-netbsd.s
@@ -0,0 +1,42 @@
+.text
+
+.globl _rt$abort_oob
+.globl __rt$abort_oob
+_rt$abort_oob:
+__rt$abort_oob:
+	/* format pc */
+	movq	(%rsp),%rax
+	movq	$15,%rdx
+	leaq	.digitchars(%rip),%r8
+	leaq    .pcstr(%rip),%r9
+.loop:
+	movq	%rax, %rcx
+	andq	$0xf, %rcx
+	movb    (%r8,%rcx),%r10b
+	movb	%r10b,(%r9,%rdx)
+	subq	$1, %rdx
+	shrq	$4, %rax
+	jnz .loop
+	/* write abort message */
+	movq	$4, %rax 	/* write(fd=%rdi, msg=%rsi, len=%rdx) */
+	movq	$2, %rdi		/* fd */
+	leaq	.msg(%rip), %rsi	/* msg */
+	movq	$(.msgend-.msg), %rdx	/* length */
+	syscall
+	/* kill self */
+	movq	$20,%rax 	/* getpid */
+	syscall	
+	movq	%rax, %rdi	/* save pid */
+	movq	$37, %rax	/* kill(pid=%rdi, sig=%rsi) */
+	movq	$6, %rsi
+	syscall
+.data
+.msg: 	/* pc name:  */
+	.ascii "0x"
+.pcstr:
+	.ascii "0000000000000000"
+	.ascii ": out of bounds access\n"
+.msgend:
+
+.digitchars:
+	.ascii "0123456789abcdef"
diff --git a/rt/start-netbsd.s b/rt/start-netbsd.s
new file mode 100644
index 0000000..d78559e
--- /dev/null
+++ b/rt/start-netbsd.s
@@ -0,0 +1,86 @@
+.section .note.netbsd.ident
+        .long	7
+	.long	4
+	.long	1
+	.ascii "NetBSD\0"
+	.p2align 2
+        .long      200000000
+
+.data
+
+/* sys._environment : byte[:][:] */
+.globl sys$__environment
+sys$__environment:
+    .envbase:
+    .quad 0 /* env size */
+    .envlen:
+    .quad 0 /* env ptr */
+
+.globl sys$__cenvp
+sys$__cenvp:
+    .quad 0
+
+.text
+/*
+ * The entry point for the whole program.
+ * This is called by the OS. In order, it:
+ *  - Sets up all argc entries as slices
+ *  - Sets up all envp entries as slices
+ *  - Converts argc/argv to a slice
+ *  - Stashes envp in sys._environment
+ *  - Stashes a raw envp copy in __cenvp (for syscalls to use)
+ *  - Calls main()
+ */
+.globl _start
+_start:
+	/* turn args into a slice */
+	movq	%rsp,%rbp
+
+	/* stack allocate sizeof(byte[:])*(argc + len(envp)) */
+	movq	(%rbp),%rax
+	leaq	16(%rbp,%rax,8), %rbx	/* argp = argv + 8*argc + 8 */
+	call    count
+	addq	%r9,%rax
+	imulq	$16,%rax
+	subq	%rax,%rsp
+	movq	%rsp, %rdx	/* saved args[:] */
+
+	/* stack allocate sizeof(byte[:])*(argc + len(envp)) */
+	movq	(%rbp),%rax
+	leaq	16(%rbp,%rax,8), %rbx	/* argp = argv + 8*argc + 8 */
+	call    count
+	addq	%r9,%rax
+	imulq	$16,%rax
+	subq	%rax,%rsp
+	movq	%rsp, %rdx	/* saved args[:] */
+
+	/* convert envp to byte[:][:] for sys._environment */
+	movq	(%rbp),%rax
+	leaq	16(%rbp,%rax,8), %rbx	/* envp = argv + 8*argc + 8 */
+	/* store envp for some syscalls to use without converting */
+	movq    %rbx,sys$__cenvp(%rip)
+	movq	%r9,%rax
+	movq	%rsp, %rcx
+	movq	%r9,.envlen(%rip)
+	movq	%rdx,.envbase(%rip)
+	call	cvt
+	movq	%rcx,%rdx
+	
+	/* convert argc, argv to byte[:][:] for args. */
+	movq	(%rbp), %rax	/* argc */
+	leaq	8(%rbp), %rbx	/* argv */
+	movq	(%rbp), %rsi	/* saved argc */
+	call	cvt
+	pushq	%rsi
+	pushq	%rdx
+
+	xorq %rbp,%rbp
+	/* call pre-main initializers */
+	call	__init__
+	/* enter the main program */
+	call	main
+	/* exit(0) */
+	xorq	%rdi,%rdi
+	movq	$1,%rax
+	syscall
+