12 Jan
2017
12 Jan
'17
1:01 p.m.
> jsr puts
> fcc 'Hello, world!',13,0
> clra
or the classic:
JMP START1
DATA2: DB . . .
DB . . .
START1: MOV DX, OFFSET DATA2
Which was heavily used because
MOV DX, OFFSET DATA3
. . .
DATA3: DB . . .
would pose "forward reference" or "undefined symbol" problems for some
assemblers.
Even for manual assembly, or 'A' mode of DEBUG.COM, it was handy to
already know the address of the data before you wrote the steps to access
it.
On Thu, 12 Jan 2017, Mouse wrote:
Mine can't do that automatically, but it can with
a little human
assist; the human would need to tell it that the memory after the jsr
is a NUL-terminated string, but that's all it would need to be told.
Not all strings are null-terminated. In CP/M, and MS-DOS INT21h Fn9, the
terminating character is '$' !
"If you are ever choosing a termination marker, choose something that
could NEVER occur in normal data!"
Also, strings may, instead of a terminating character, be specified with a
length, or with a start and end address.