assembler - translates assembly language to object files
compiler - translates high level code to object files
linker - converts object files to binary code
loader - loads binary code into microcontroller

program to add two 32bit numbers
he wants a header with:
program purpose
input
output
author
date
description

assemblers are two-pass
replace what symbols you can on the first pass
by the second pass, you should have all symbols

#include "msp430.h"
NAME main
PUBLIC main
ORG 0xF000
lint1: DC32 0x45678923
lint2: DC32 0x23456789
ORG 0xFFFE
DC16 main
ORG 0x0400
lsumd: DS32 1
lsumi: DS32 1

continued...

EQU makes a constant
for example:
tf EQU 25

for strings:

s1: DB 'ABCD' ; allocates 4 bytes, no null
s2: DB "ABCD" ; allocates 5 bytes, null at the end

problem:
write assembly prog that processes an input tstring to find the number of E's in the string
msp430 has 6 parallel ports
PxDIR = 0x00 for input
PxDIR = 0xFF for output
PxOUT for writing out bits
PxIN for reading input data