work on openbsd port

- fix start assembly
- update syscall numbers to match openbsd
- add openbsd note section

1 files changed, 42 insertions, 21 deletions

diff --git a/rt/start-openbsd.s b/rt/start-openbsd.s
index 54cd0ce..e73c226 100644
--- a/rt/start-openbsd.s
+++ b/rt/start-openbsd.s
@@ -1,15 +1,25 @@
+.section ".note.openbsd.ident", "a"
+	.p2align 2
+	.long   8
+	.long   4
+	.long   1
+	.ascii "OpenBSD\0"
+	.long   0
+	.p2align 2
+
 .data
-/* std._environment : byte[:][:] */
+
+/* sys._environment : byte[:][:] */
 .globl sys$__environment
 sys$__environment:
-.envbase:
-.quad 0 /* env size */
-.envlen:
-.quad 0 /* env ptr */
+    .envbase:
+    .quad 0 /* env size */
+    .envlen:
+    .quad 0 /* env ptr */
 
 .globl sys$__cenvp
 sys$__cenvp:
-.quad 0
+    .quad 0
 
 .text
 /*
@@ -18,25 +28,37 @@ sys$__cenvp:
  *  - Sets up all argc entries as slices
  *  - Sets up all envp entries as slices
  *  - Converts argc/argv to a slice
- *  - Stashes envp in std._environment
+ *  - 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	(%rdi),%rax
-	leaq	16(%rdi,%rax,8), %rbx	/* argp = argv + 8*argc + 8 */
+	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 std._environment */
-	movq	(%rdi),%rax
-	leaq	16(%rdi,%rax,8), %rbx	/* envp = argv + 8*argc + 8 */
-	/* store envp for some syscalls to use without spurious conversion. */
+	/* 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
@@ -44,18 +66,17 @@ _start:
 	movq	%rdx,.envbase(%rip)
 	call	cvt
 	movq	%rcx,%rdx
-
+	
 	/* convert argc, argv to byte[:][:] for args. */
-	movq	(%rdi), %rax	/* argc */
-	leaq	8(%rdi), %rbx	/* argv */
-	movq	(%rdi), %rsi	/* saved argc */
-	call    cvt
-	pushq   %rsi
-	pushq   %rdx
+	movq	(%rbp), %rax	/* argc */
+	leaq	8(%rbp), %rbx	/* argv */
+	movq	(%rbp), %rsi	/* saved argc */
+	call	cvt
+	pushq	%rsi
+	pushq	%rdx
 
 	/* call pre-main initializers */
 	call	__init__
-
 	/* enter the main program */
 	call	main
 	/* exit(0) */