System Software – SIC/XE Program to write a subroutine for SIC that will read a record into a buffer

Problem Statement

Write a subroutine for SIC that will read a record into a buffer. The record may be any length from 1 to 100 bytes. The end of record is marked with a “null” character (ASCII code 00). The subroutine should place the length of the record read into a variable named LENGTH.

Solution

Line Number	Code	Comments
1	RDREC LDX ZERO
2	RLOOP TD INDEV
3	JEQ RLOOP
4	RD INDEV
5	COMP NULL
6	JEQ EXIT
7	STCH BUFFER, X
8	TIX K100
9	JLT RLOOP
10	EXIT STX LENGTH
11	RSUB
12	ZERO WORD 0
13	NULL WORD 0
14	K100 WORD 1
15	INDEV BYTE X ‘F1’
16	LENGTH RESW 1
17	BUFFER RESB 100