From 7d412a05b2eb563f268d81387be0dacd1b77cac2 Mon Sep 17 00:00:00 2001
From: "B. Watson" <yalhcru@gmail.com>
Date: Sat, 2 Jan 2016 21:35:39 -0500
Subject: leave title screen showing while loading (not quite right yet)

---
 timed_getch.s | 108 +++++++++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 96 insertions(+), 12 deletions(-)

(limited to 'timed_getch.s')

diff --git a/timed_getch.s b/timed_getch.s
index 8675290..a5ac4d5 100644
--- a/timed_getch.s
+++ b/timed_getch.s
@@ -1,26 +1,110 @@
 
- .export _timed_getch, _set_jiffy_timer
- .import _cgetc
+ .export _timed_getch, _set_jiffy_timer, _agetc, _numgetc, _yngetc, _lcgetc
+ .import _cgetc, _cblank
 
-_set_jiffy_timer:
- sei
- sta 540
- stx 541
+ .include "atari.inc"
+
+_set_jiffy_timer: ; called by jsleep() also.
+ sei          ; disable IRQ while setting timer
+ sta CDTMV3
+ stx CDTMV3+1
  cli
  rts
 
 _timed_getch:
  jsr _set_jiffy_timer
 wait4key:
- lda 540
- ora 541
- beq done
- ldx 764
- inx
+ lda CDTMV3   ; has timer counted down to 0?
+ ora CDTMV3+1
+ beq done     ; yes, return(-1)
+ lda CH       ; no, check for a keypress
+          ; ...but don't let the capslock or inverse keys count
+			 ; as a keypress, here.
+
+ cmp #$ff ; no key pressed
+ beq wait4key
+ and #$3f ; mask shift/control bits
+ cmp #$3c ; caps-lock
+ beq wait4key
+ cmp #$27 ; inverse (atari) key
  beq wait4key
- jmp _cgetc
 
+ jmp _agetc ; user hit a key, read it.
+ 
 done:
  lda #$ff ; return -1
  tax
  rts
+
+; _agetc removes the inverse-video bit, and if
+; a control key is pressed, it turns it into the non-control version
+; (e.g. ^A = lowercase a). Keys that can't be mapped to regular ASCII
+; (such as clear, delete, escape) are replaced with a space.
+; extern char lcgetc();
+_agetc:
+; lda #0      ; show cursor
+; sta CRSINH
+; lda #$20
+; jsr _cblank
+
+ jsr _cgetc ; get ATASCII code of keypress
+
+ ; special cases
+ cmp #$9b   ; enter key, return as-is
+ beq ok
+ cmp #$7e   ; backspace
+ beq ok
+
+ ; everything else
+ and #$7f   ; strip bit 7 (inverse)
+ bne notnull
+ lda #$20   ; map null (heart, ctrl-,) to space
+notnull:
+ cmp #$20
+ bcs notcontrol
+ ora #$60   ; 1 - 31 map to 96 - 127
+notcontrol:
+ cmp #$7c ; | (pipe, vertical bar) allowed as-is.
+ beq ok
+ cmp #$7a ; rest of range $7b - $7f is unmappable.
+ bcc ok   ; (remember, $7e, backspace, was handled above)
+ lda #$20
+ok:
+; ldx #$01   ; hide cursor
+; stx CRSINH
+ rts
+
+_lcgetc:
+ jsr _agetc
+ cmp #'A'
+ bcc ok
+ cmp #'Z'+1
+ bcs ok
+ eor #$20   ; lowercase it
+ bcc ok
+
+_numgetc:
+ jsr _agetc
+ cmp #$9b
+ beq ok
+ cmp #$7e
+ beq ok
+ cmp #$61   ; allow 'a' for "all"
+ beq ok
+ cmp #'0'
+ bcc _numgetc
+ cmp #'9'+1
+ bcc ok
+ bcs _numgetc
+
+_yngetc:
+ sta FR0 ; stash default arg
+ jsr _lcgetc
+ cmp #'y'  ; return y or n immediately
+ beq ok
+ cmp #'n'
+ beq ok
+ lda FR0     ; otherwise, check for default arg
+ beq _yngetc ; no default, get another keypress
+ rts         ; else return the default
+
-- 
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