KermMartian: Created page with "One of the easiest ways to communicate with the user is through text. The OS offers a slew of routines, but here are a few more to add to your list of routines: = PutSI = Sta..."

2016-02-05T06:35:29Z

Created page with "One of the easiest ways to communicate with the user is through text. The OS offers a slew of routines, but here are a few more to add to your list of routines: = PutSI = Sta..."

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One of the easiest ways to communicate with the user is through text. The OS offers a slew of routines, but here are a few more to add to your list of routines:

= PutSI =
Standing for "Put String Immediate," a routine like this can really add up to be a wonderful way to save memory, especially for programs relying heavily on text. What you do is call this routine with your text data directly following the call. For example:

call PutSI
.db 3,3,"String",0

Here is the code:

PutSI:
pop hl
ld c,(hl)
inc hl
ld b,(hl)
inc hl
ld (curRow),bc
bcall(_PutS)
jp (hl)

To give an idea of how much memory it saves, you save 1 byte after using this routine twice (it makes up for the size of the routine) and saves an additional 7 bytes each time it is used.
= VPutSI =
Along the same lines as PutSI:

VPutSI:
pop hl
ld c,(hl)
inc hl
ld b,(hl)
inc hl
ld (penCol),bc
bcall(_VPutS)
jp (hl)

= PutS_App =
To use bcall(_PutS), the string must be in RAM. In Apps, this means you need to copy the string to RAM before displaying it. Or, you could make a routine like this:

PutS_App:
;Inputs:
; HL points to the zero-terminated string
ld a,(hl)
or a
ret z
inc hl
bcall(_PutC)
jr PutS_App

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[[Category:Z80 Assembly]]
[[Category:Z80 Heaven]]

Z80:Text Routines - Revision history

KermMartian: Created page with "One of the easiest ways to communicate with the user is through text. The OS offers a slew of routines, but here are a few more to add to your list of routines: = PutSI = Sta..."