30 May
1998
30 May
'98
4:45 p.m.
On Sun, 31 May 1998, Tony Duell wrote:
That's quite apart from the fact that AFAIK the
Apple ][ keyboard doesn't
generate interrupts.
That's correct. I should've stated that in my previous message. The
Apple had virtually no interrupts. Everything was software driven. The
only way to generate interrupts was either to add hardware to allow for
the triggering of standard interrupt or a non-maskable interrupt (NMI), or
to JuMP to a location with a #$00, which caused the CPU to jump to your
BREAK location (Opcode $00 in 6502 machine language is the BReaK
instruction).
Sam Alternate e-mail: dastar(a)siconic.com
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