Z80 TRAP and CP/M

[Chuck Guzis]

On 4/2/2006 at 7:12 PM Roy J. Tellason wrote:

>And why it was necessary to stuff parameters into registers,  when it's
>easy enough to put 'em on the stack,  among other things.

Well, memory fetches are slower than register references for one.  It
requires stack space, for another.  And the 8080 code to access the
arguments, while not awful, is somewhat clumsy:

	lxi	h, 2
	dad	sp
	mov	c,m
	inx	h
	mov	b,m

....or something like that to grab a word off the stack into BC.

Cheers,
Chuck