From 542474e9201cc81bda1171c7d438a154395a19f6 Mon Sep 17 00:00:00 2001
From: Karol Stasiak <karol.m.stasiak@gmail.com>
Date: Tue, 31 Mar 2020 17:59:50 +0200
Subject: [PATCH] Improve `readkey` on CBM targets. PET improvements.

---
 include/keyboard.mfk   | 41 +++++++++++++++++++++++++++++++++++++++++
 include/pet.ini        |  5 ++++-
 include/pet_kernal.mfk | 18 ++++++++++++++++++
 3 files changed, 63 insertions(+), 1 deletion(-)

diff --git a/include/keyboard.mfk b/include/keyboard.mfk
index 7d51372b..8da5706a 100644
--- a/include/keyboard.mfk
+++ b/include/keyboard.mfk
@@ -7,6 +7,8 @@ const byte KEY_ENTER = 13
 
 #if CBM_64
 noinline asm byte readkey() {
+    LDA #0
+    STA $C6
 __read_key__start:
     LDA $C6
     BEQ __read_key__start
@@ -18,6 +20,8 @@ __read_key__start:
 
 #if CBM_128
 noinline asm byte readkey() {
+    LDA #0
+    STA $D0
 __read_key__start:
     LDA $D0
     BEQ __read_key__start
@@ -30,6 +34,8 @@ __read_key__start:
 
 #if CBM_264
 noinline asm byte readkey() {
+    LDA #0
+    STA $EF
 __read_key__start:
     LDA $EF
     BEQ __read_key__start
@@ -42,6 +48,8 @@ __read_key__start:
 
 #if CBM_VIC
 noinline asm byte readkey() {
+    LDA #0
+    STA $C6
 __read_key__start:
     LDA $C6
     BEQ __read_key__start
@@ -51,6 +59,39 @@ __read_key__start:
 #endif
 
 
+#if CBM_PET
+
+#if not(PET2001_SUPPORT) && not(PET3000_SUPPORT) && not(PET4000_SUPPORT)
+#error At least one of PET2000_SUPPORT, PET3000_SUPPORT, PET4000_SUPPORT has to be defined
+#endif
+
+noinline asm byte readkey() {
+#if PET2001_SUPPORT
+    JSR is_pet2000
+    BNE __read_key__start_new
+    // ROM 1.0:
+    LDA #0
+    STA $20D
+__read_key__start1:
+    LDA $20D
+    BEQ __read_key__start1
+    LDA $20F
+    RTS
+
+    // ROM 2.0 and above:
+__read_key__start_new:
+    LDA #0
+    STA $9E
+__read_key__start2:
+    LDA $9E
+    BEQ __read_key__start2
+    LDA $026F
+    RTS
+}
+#define OK = 1
+#endif
+
+
 #if ATARI_8
 noinline asm byte readkey() {
     lda #$C
diff --git a/include/pet.ini b/include/pet.ini
index fa08b27f..34e89040 100644
--- a/include/pet.ini
+++ b/include/pet.ini
@@ -2,7 +2,7 @@
 arch=nmos
 encoding=oldpetscii
 screen_encoding=petscr
-modules=loader_0401,pet_kernal,default_panic
+modules=loader_0401,pet_kernal,default_panic,stdlib
 
 
 [allocation]
@@ -18,6 +18,9 @@ WIDESCREEN=0
 KEYBOARD=1
 JOYSTICKS=0
 HAS_BITMAP_MODE=0
+PET2000_SUPPORT=1
+PET3000_SUPPORT=1
+PET4000_SUPPORT=1
 
 [output]
 style=single
diff --git a/include/pet_kernal.mfk b/include/pet_kernal.mfk
index 59376250..e401ea61 100644
--- a/include/pet_kernal.mfk
+++ b/include/pet_kernal.mfk
@@ -11,3 +11,21 @@ asm void putchar(byte register(a) char) @$FFD2 extern
 inline void new_line() {
     putchar(13)
 }
+
+inline asm set_zero is_pet2000() {
+    ? LDA #$CA
+    CMP $FFFB
+    ? RTS
+}
+
+inline asm set_zero is_pet3000() {
+    ? LDA #$FC
+    CMP $FFFB
+    ? RTS
+}
+
+inline asm set_zero is_pet4000() {
+    ? LDA #$FD
+    CMP $FFFB
+    ? RTS
+}