From ac88639f4a9bdcb40388d6afd04dae032f74b951 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Stephan=20M=C3=BChlstrasser?= <stephan.muehlstrasser@web.de>
Date: Sat, 29 Nov 2014 20:07:30 +0100
Subject: [PATCH] Implemented cursor functionality.

---
 cfg/c1p.cfg          |  3 ++-
 libsrc/c1p/cgetc.s   | 25 +++++++++++++++++++++++--
 libsrc/c1p/extzp.inc |  2 +-
 libsrc/c1p/extzp.s   |  8 +++-----
 4 files changed, 29 insertions(+), 9 deletions(-)

diff --git a/cfg/c1p.cfg b/cfg/c1p.cfg
index 46015017b..2f48dd084 100644
--- a/cfg/c1p.cfg
+++ b/cfg/c1p.cfg
@@ -14,7 +14,8 @@ SYMBOLS {
     __HIMEM__:     type = weak, value = $2000; # Presumed RAM end
 }
 MEMORY {
-    ZP:       file = "", define = yes, start = $0002, size = $001A + $0005;
+    # for size of ZP see runtime/zeropage.s and c1p/extzp.s
+    ZP:       file = "", define = yes, start = $0002, size = $001A + $0006;
     RAM:      file = %O, define = yes, start = %S, size = __HIMEM__ - __STACKSIZE__ - %S;
 }
 SEGMENTS {
diff --git a/libsrc/c1p/cgetc.s b/libsrc/c1p/cgetc.s
index a73866a56..b17e76572 100644
--- a/libsrc/c1p/cgetc.s
+++ b/libsrc/c1p/cgetc.s
@@ -2,7 +2,28 @@
 ; char cgetc (void);
 ;
         .export         _cgetc
+        .import         cursor
+
         .include        "c1p.inc"
+        .include        "extzp.inc"
 
-; Direct use of input routine from 65V PROM MONITOR
-_cgetc = INPUTC
+; Input routine from 65V PROM MONITOR, show cursor if enabled
+_cgetc:
+        lda     cursor          ; show cursor?
+        beq     nocursor
+        ldy     CURS_X
+        lda     (SCREEN_PTR),y  ; fetch current character
+        sta     CURS_SAV        ; save it
+        lda     #$A1            ; full white square
+        sta     (SCREEN_PTR),y  ; store at cursor position
+nocursor:
+        jsr     INPUTC
+        pha                     ; save retrieved character
+        lda     cursor          ; was cursor on?
+        beq     nocursor2
+        lda     CURS_SAV        ; fetch saved character
+        ldy     CURS_X
+        sta     (SCREEN_PTR),y  ; store at cursor position
+nocursor2:
+        pla                     ; restore retrieved character
+        rts
diff --git a/libsrc/c1p/extzp.inc b/libsrc/c1p/extzp.inc
index 0f9632df2..c5bb2b585 100644
--- a/libsrc/c1p/extzp.inc
+++ b/libsrc/c1p/extzp.inc
@@ -4,4 +4,4 @@
 
 ; ------------------------------------------------------------------------
 
-        .globalzp       CURS_X, CURS_Y, SCR_LINELEN, SCREEN_PTR
+        .globalzp       CURS_X, CURS_Y, CURS_SAV, SCR_LINELEN, SCREEN_PTR
diff --git a/libsrc/c1p/extzp.s b/libsrc/c1p/extzp.s
index 139feffde..c55156f82 100644
--- a/libsrc/c1p/extzp.s
+++ b/libsrc/c1p/extzp.s
@@ -11,13 +11,11 @@
 
 .segment        "EXTZP" : zeropage
 
-; The following values get initialized from a table in the startup code.
-; While this sounds crazy, it has reasons that have to do with modules (and
-; we have the space anyway). So when changing anything, be sure to adjust the
-; initializer table
 CURS_X:         .byte   0
 CURS_Y:         .byte   0
+CURS_SAV:       .byte   0
 SCR_LINELEN:    .byte   24
 SCREEN_PTR:     .res    2
 
-; size 5
+; size 6
+; Adjust size of this segment in c1p.cfg if the size changes
-- 
2.39.5