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cc65/libsrc/apple2/textframe.s
Oliver Schmidt e47485f925 Added CONIO cursor support.
For quite some time I deliberately didn't add cursor support to the Apple II CONIO imöplementation. I consider it inappropriate to increase the size of cgetc() unduly for a rather seldom used feature.

There's no hardware cursor on the Apple II so displaying a cursor during keyboard input means reading the character stored at the cursor location, writing the cursor character, reading the keyboard and finally writing back the character read initially.

The naive approach is to reuse the part of cputc() that determines the memory location of the character at the cursor position in order to read the character stored there. However that means to add at least one additional JSR / RTS pair to cputc() adding 4 bytes and 12 cycles :-( Apart from that this approach means still a "too" large cgetc().

The approach implemented instead is to include all functionality required by cgetc() into cputc() - which is to read the current character before writing a new one. This may seem surprising at first glance but an LDA(),Y / TAX sequence adds only 3 bytes and 7 cycles so it cheaper than the JSR / RTS pair and allows to brings down the code increase in cgetc() down to a reasonable value.

However so far the internal cputc() code in question saved the X register. Now it uses the X register to return the old character present before writing the new character for cgetc(). This requires some rather small adjustments in other functions using that internal cputc() code.
2016-06-19 15:03:20 +02:00

109 lines
3.2 KiB
ArmAsm

;
; Oliver Schmidt, 10.03.2004
;
; void __fastcall__ textframexy (unsigned char x, unsigned char y,
; unsigned char width, unsigned char height,
; unsigned char style);
; void __fastcall__ textframe (unsigned char width, unsigned char height,
; unsigned char style);
;
.ifdef __APPLE2ENH__
.export _textframexy, _textframe
.import popa, pusha, _gotoxy
.import chlinedirect, cvlinedirect
.include "zeropage.inc"
.include "apple2.inc"
WIDTH = ptr1
HEIGHT = ptr1+1
XORIGIN = ptr2
YORIGIN = ptr2+1
_textframexy:
sec
bra :+
_textframe:
clc
: ldx INVFLG
phx ; Save character display mode
ldx #$FF
stx INVFLG ; Set normal character display mode
pha ; Save index
jsr popa ; Get height
sta HEIGHT
jsr popa ; Get width
sta WIDTH
lda CH
ldx CV
bcc noxy
jsr popa ; Get y
tax
jsr popa ; Get x
noxy: sta XORIGIN
stx YORIGIN
plx ; Restore index
loop: lda XOFFS,x
clc
bpl :+ ; Relative to left edge?
adc WIDTH
: adc XORIGIN
jsr pusha
lda YOFFS,x
clc
bpl :+ ; Relative to top?
adc HEIGHT
: adc YORIGIN
jsr _gotoxy ; Call this one, will pop params
txa
tay
lsr ; Get bit 0 (vline) into carry
lda LENGTH,x
phx ; Save index
ldx CHAR,y
bcc hline
clc
adc HEIGHT
jsr cvlinedirect
bra next
hline: adc WIDTH
jsr chlinedirect
next: plx ; Restore index
inx
txa
and #$03 ; Mask style
bne loop
pla
sta INVFLG ; Restore character display mode
rts
.rodata
; 2 styles with 4 lines each make up 8 entries per table
; - even entry numbers mean horizontal lines
; - odd entry numbers mean vertical lines
; x offset for the line starting point
; - a positive value means relative to the frame left edge
; - a negative value menas relative to the frame right edge
XOFFS: .byte 0, 0, 0, <-2, 1, 0, 1, <-2
; y offset for the line starting point
; - a positive value means relative to the frame top
; - a negative value menas relative to the frame bottom
YOFFS: .byte 0, 1, <-2, 1, 0, 0, <-2, 0
; length of the line relative to the frame size
; - a negative value for hlines means shorter than the width
; - a negative value for vlines menas shorter than the height
LENGTH: .byte 0, <-2, 0, <-2, <-2, 0, <-2, 0
; character to use for drawing the line
; - hibit set means normal printable character
; - hibit clear means MouseText character
CHAR: .byte '_'|$80, '_', 'L', 'Z', 'L', 'Z', '_'|$80, '_'
.endif ; __APPLE2ENH__