Programming instructions

SYLLABLES: A syllable can take several forms. It can be a value symbol,

a period ( . ), a flexowriter input pseudo-instruction (flex or char), or a

constant (a word enclosed in parentheses).

Examples:

100

lz2

flex abc

flex now

K” a + l)

a bcdef

WORDS: A word is a string of syllables connected by the arithmetic opera-

tors plus, minus, space, AND or OR, delimited on the left by tab, carriage

return, left parenthesis, or equals sign, and on the right by a tab or car-

riage return. A word may be a single number or symbol so delimited, or a

string of symbols connected by the operators. If the word is delimited on

the left by an equals sign then the symbol to the left of the equals sign is

assigned a value equal to that of the word. Otherwise, the word is a storage

word and will become part of the binary version of the program being

assembled. The arithmetic operators, plus and space both mean add,

while the operator minus means subtract.

Examples:

sad Kr)

lac a *>

1000 - 2oa

add b + 2*)

jmp. - 24

a+b-c-2a

lac (add a + 1)r)

THE CHARACTER SLASH ( / ): The slash has two meanings. If immediately

preceded by a tab or carriage return then slash initiates a comment, which

is terminated by the next tab or carriage return. If slash is preceded by a

word, then the address part of the word indicates the address into which

the next instruction or data word will go. Normally, the first instruction or

data word goes into register 22 and succeeding instructions or data words

into succeeding registers. If the programmer wishes to break this sequence

or wishes

to start translating into some register other than 22, then a

slash may be used to set the new address.

INDIRECT ADDRESSING: Indirect addressing is indicated by the symbol, i

which has the value 20000.

Example: lac i abc

THE CHARACTER PERIOD ( . ): The period ( . ) has as its value the current

address.

Example: dac . is equivalent to

a, dac a