Source code for BASIC

From: CLASSICCMP_at_trailing-edge.com <(CLASSICCMP_at_trailing-edge.com)>
Date: Wed Feb 16 15:49:57 2000

>Looking at the tape, I see that the words "END OF FILE BAS65.PTP"
>are punched at the end of the tape in sort of pseudo dot-matrix
>characters. Does the "PTP" extension tell us anything?

"Paper TaPe" in DEC-ese.

> Looking at
>the start of the tape:
>"MICRO-SOFT BAS65.PTP [2601,1260] 29-JUL-77 15:27:58"

That makes sense, Microsoft was cross-assembling on PDP-10's at
the time, and [2601,1260] would be the PPN code for an account.

For the first couple of years Microsoft was using the hyphenated
form.

>Looking through the first few feet of "real data"...
>
>No high bits, the first few bytes are:
>00111011 x3b ';' (was hoping for the start of an assembly comment)
>00110010 x32 '2' (nope, looks like some sort of hex...)
>00110000 x30 '0'
>01000001 x41 'A'
>00110000 x30 '0'
>00110000 x30 '0'
>00110000 x30 '0'
>00110011 x33 '3'
>00111001 x39 '9'
>01000001 x41 'A'

That makes some sense, "20" is the 6502 opcode for a JSR (jump to
subroutine). The next two bytes are presumably the subroutine's
address, and "39" is the 6502 opcode for an AND abolute,Y instruction.

Tim.
Received on Wed Feb 16 2000 - 15:49:57 GMT