Lee Hart July 2014

Here is an exact sample of the actual code that RCA's assembler format produced.
 Their assembler used ".." as the comment delimiter instead of ";". The ";" was
 used for the "continued on next line" delimiter by the UT4 and IDIOT monitors.

Remember that RCA expected a teletype read/punch as the only mass storage device.
 There could be only ONE input file, and ONE output file. So they wanted their
 single output file format to serve both purposes (.hex and .prn file). It is
 readable by the UT4 monitor for downloading, and by a human reading the 
printout.

[The "!M" in the first line, is the UT4 "load memory" command. The syntax
is a hex memory address, followed by hex bytes, with space separators. - Herb]

The first column is the address. The colon ends the part that UT4/IDIOT reads.
 Then a line number (important because RCA's editor was line-oriented). The
 RCA assembler source file began each [assembly source] line with the line number.

!M
0000 ;        0001        ..THIS IS A COMMENT
0000 ;        0002
0000 ;        0003        ..CONSTANTS
0000 ;        0004 DATA    EQU    2
0000 ;        0005 STATUS    EQU    3
0000 ;        0006
0000 ;        0007        ..REGISTERS
0000 ;        0008 STK    EQU    2
0000 ;        0009 PC        EQU    3
0000 ;        0010
0100 ;        0011        ORG 100H
0100 E3;    0012 CLEAR    SEX PC
0101 6102;    0013        OUT 1; DC 2    ..SELECT UART BOARD
0103 631D;    0014        OUT 3; DC 1DH    ..SET UART FOR 8 DATA,
0105 ;        0015                ..  2 STOP, NO PARITY
0105 E2;    0016        SEX STK        ..FOR INPUT BYTE
0106 6A;    0017        INP 0AH        ..READ DATA

The Avocet [brand] and HMDS [RCA hardware development system] assemblers could 
output in this format because then it could be loaded by RCA's monitors.


- Lee Hart