Re: programming in Assembly

Your hints were sufficient to get me to a working 64-bit program:

```
.section ".note.openbsd.ident", "a"
.p2align 2
.long 0x8
.long 0x4
.long 0x1
.ascii "OpenBSD\0"
.long 0x
.p2align 2

.section .text
.globl _start
_start:
mov $1, %rax
xor %rdi, %rdi
syscall
```

I'd been playing with some other nasm-based examples, and assumed
`syscall` was part of the syntactic differences between `as` and
`nasm` until you set me straight. Thanks again!