From 11629bcf990bcc91326f33cb668749a9fa79c9eb Mon Sep 17 00:00:00 2001
From: Marco van den Heuvel <blackystardust68@yahoo.com>
Date: Fri, 27 Apr 2018 14:22:41 -0700
Subject: [PATCH] Added C65/C64DX accelerator code and documentation.

---
 asminc/accelerator.inc              |  9 ++++
 doc/c64.sgml                        |  3 ++
 doc/funcref.sgml                    | 67 +++++++++++++++++++++++++++
 include/accelerator.h               | 37 +++++++++++++++
 libsrc/c64/acc_c65_speed.s          | 70 +++++++++++++++++++++++++++++
 libsrc/c64/acc_detect_c65.s         | 55 +++++++++++++++++++++++
 testcode/lib/accelerator/Makefile   |  6 ++-
 testcode/lib/accelerator/c65-test.c |  8 ++++
 8 files changed, 254 insertions(+), 1 deletion(-)
 create mode 100755 libsrc/c64/acc_c65_speed.s
 create mode 100755 libsrc/c64/acc_detect_c65.s
 create mode 100644 testcode/lib/accelerator/c65-test.c

diff --git a/asminc/accelerator.inc b/asminc/accelerator.inc
index 0c687b2ad..a92b65ff9 100644
--- a/asminc/accelerator.inc
+++ b/asminc/accelerator.inc
@@ -60,3 +60,12 @@ CHAMELEON_DISABLE_REGS = $FF
 CHAMELEON_CFGTUR_LIMIT_1MHZ = %00001100
 CHAMELEON_CFGTUR_LIMIT_NONE = %10000000
 
+
+; ---------------------------------------------------------------------------
+; C65/C64DX in C64 mode
+
+C65_VICIII_KEY    := $D02F
+C65_VICIII_CTRL_B := $D031
+
+C65_VICIII_UNLOCK_1 = $A5
+C65_VICIII_UNLOCK_2 = $96
diff --git a/doc/c64.sgml b/doc/c64.sgml
index c037b1e0e..800314fec 100644
--- a/doc/c64.sgml
+++ b/doc/c64.sgml
@@ -177,14 +177,17 @@ url="funcref.html" name="function reference"> for declaration and usage.
 <itemize>
 <item>detect_c128
 <item>detect_c64dtv
+<item>detect_c65
 <item>detect_chameleon
 <item>detect_scpu
 <item>get_c128_speed
 <item>get_c64dtv_speed
+<item>get_c65_speed
 <item>get_chameleon_speed
 <item>get_scpu_speed
 <item>set_c128_speed
 <item>set_c64dtv_speed
+<item>set_c65_speed
 <item>set_chameleon_speed
 <item>set_scpu_speed
 </itemize>
diff --git a/doc/funcref.sgml b/doc/funcref.sgml
index 09ee27e4a..edca7745e 100644
--- a/doc/funcref.sgml
+++ b/doc/funcref.sgml
@@ -70,14 +70,17 @@ function.
 <itemize>
 <item><ref id="detect_c128" name="detect_c128">
 <item><ref id="detect_c64dtv" name="detect_c64dtv">
+<item><ref id="detect_c65" name="detect_c65">
 <item><ref id="detect_chameleon" name="detect_chameleon">
 <item><ref id="detect_scpu" name="detect_scpu">
 <item><ref id="get_c128_speed" name="get_c128_speed">
 <item><ref id="get_c64dtv_speed" name="get_c64dtv_speed">
+<item><ref id="get_c65_speed" name="get_c65_speed">
 <item><ref id="get_chameleon_speed" name="get_chameleon_speed">
 <item><ref id="get_scpu_speed" name="get_scpu_speed">
 <item><ref id="set_c128_speed" name="set_c128_speed">
 <item><ref id="set_c64dtv_speed" name="set_c64dtv_speed">
+<item><ref id="set_c65_speed" name="set_c65_speed">
 <item><ref id="set_chameleon_speed" name="set_chameleon_speed">
 <item><ref id="set_scpu_speed" name="set_scpu_speed">
 </itemize>
@@ -2969,6 +2972,26 @@ used in presence of a prototype.
 </quote>
 
 
+<sect1>detect_c65<label id="detect_c65"><p>
+
+<quote>
+<descrip>
+<tag/Function/Check for the presence of a C65/C64DX in C64 mode.
+<tag/Header/<tt/<ref id="accelerator.h" name="accelerator.h">/
+<tag/Declaration/<tt/unsigned char detect_c65 (void);/
+<tag/Description/The function returns a 1 if a C65/C64DX in C64 mode has been detected.
+<tag/Notes/<itemize>
+<item>The function is specific to the C64.
+</itemize>
+<tag/Availability/cc65 (not all platforms)
+<tag/See also/
+<ref id="get_c65_speed" name="get_c65_speed">,
+<ref id="set_c65_speed" name="set_c65_speed">,
+<tag/Example/None.
+</descrip>
+</quote>
+
+
 <sect1>detect_chameleon<label id="detect_chameleon"><p>
 
 <quote>
@@ -3592,6 +3615,28 @@ header files define constants that can be used to check the return code.
 </quote>
 
 
+<sect1>get_c65_speed<label id="get_c65_speed"><p>
+
+<quote>
+<descrip>
+<tag/Function/Get the current speed of the C65/C64DX in C64 mode.
+<tag/Header/<tt/<ref id="accelerator.h" name="accelerator.h">/
+<tag/Declaration/<tt/unsigned char get_c65_speed (void);/
+<tag/Description/The function returns the current speed of the C65/C64DX in C64 mode.
+<tag/Notes/<itemize>
+<item>The function is specific to the C64.
+<item>The function does not check for the presence of a C65/C64DX in C64 mode.
+<item>See the accelerator.h header for the speed definitions.
+</itemize>
+<tag/Availability/cc65 (not all platforms)
+<tag/See also/
+<ref id="detect_c65" name="detect_c65">,
+<ref id="set_c65_speed" name="set_c65_speed">,
+<tag/Example/None.
+</descrip>
+</quote>
+
+
 <sect1>get_chameleon_speed<label id="get_chameleon_speed"><p>
 
 <quote>
@@ -6231,6 +6276,28 @@ clean-up when exitting the program.
 </quote>
 
 
+<sect1>set_c65_speed<label id="set_c65_speed"><p>
+
+<quote>
+<descrip>
+<tag/Function/Set the current speed of the C65/C64DX in C64 mode.
+<tag/Header/<tt/<ref id="accelerator.h" name="accelerator.h">/
+<tag/Declaration/<tt/unsigned char __fastcall__ set_c65_speed (unsigned char speed);/
+<tag/Description/The function returns the speed after trying to set the speed of the C65/C64DX in C64 mode.
+<tag/Notes/<itemize>
+<item>The function is specific to the C64.
+<item>The function does not check for the presence of a C65/C64DX in C64 mode.
+<item>See the accelerator.h header for the speed definitions.
+</itemize>
+<tag/Availability/cc65 (not all platforms)
+<tag/See also/
+<ref id="detect_c65" name="detect_c65">,
+<ref id="get_c65_speed" name="get_c65_speed">,
+<tag/Example/None.
+</descrip>
+</quote>
+
+
 <sect1>set_chameleon_speed<label id="set_chameleon_speed"><p>
 
 <quote>
diff --git a/include/accelerator.h b/include/accelerator.h
index d29b73467..a5e6dbb28 100644
--- a/include/accelerator.h
+++ b/include/accelerator.h
@@ -226,6 +226,43 @@ unsigned char detect_chameleon (void);
  * 0x01  : C64 Chameleon cartridge present
  */
 
+
+/* C65/C64DX in C64 mode */
+
+unsigned char __fastcall__ set_c65_speed (unsigned char speed);
+
+/* Set the speed of the C65/C64DX CPU, using SPEED_SLOW will switch to
+ * 1 Mhz mode, SPEED_3X or SPEED_FAST will switch to 3.5 Mhz (fast) mode.
+ *
+ * Note that any value higher or equal to SPEED_3X will switch to fast mode.
+ *
+ * This function will return the actual speed the CPU is at after trying
+ * to set the requested speed, to my knowledge the switching should not fail.
+ *
+ * This function does not check for the presence of a C65/C64DX in C64 mode,
+ * make sure you use 'detect_c65();' before using.
+ */
+
+unsigned char get_c65_speed (void);
+
+/* Get the speed of the C65/C64DX CPU.
+ *
+ * Possible return values:
+ * SPEED_SLOW  : Slow mode
+ * SPEED_3X    : Fast mode
+ *
+ * This function does not check for the presence of a C65/C64DX in C64 mode,
+ * make sure you use 'detect_c65();' before using.
+ */
+
+unsigned char detect_c65 (void);
+
+/* Check for the presence of a C65/C64DX in C64 mode.
+ *
+ * Possible return values:
+ * 0x00  : C65/C64DX in C64 mode not present
+ * 0x01  : C65/C64DX in C64 mode present
+ */
 /* End of accelerator.h */
 #endif
 
diff --git a/libsrc/c64/acc_c65_speed.s b/libsrc/c64/acc_c65_speed.s
new file mode 100755
index 000000000..94fa50e91
--- /dev/null
+++ b/libsrc/c64/acc_c65_speed.s
@@ -0,0 +1,70 @@
+;
+; Marco van den Heuvel, 2018-04-27
+;
+
+; unsigned char __fastcall__ set_c65_speed (unsigned char speed);
+;
+;/* Set the speed of the C65 CPU, using SPEED_SLOW will switch to
+; * 1 Mhz mode, SPEED_3X or SPEED_FAST will switch to 3.5 Mhz (fast) mode.
+; *
+; * Note that any value higher or equal to SPEED_3X will switch to fast mode.
+; *
+; * This function will return the actual speed the CPU is at after trying
+; * to set the requested speed, to my knowledge the switching should not fail.
+; *
+; * This function does not check for the presence of a C65/C64DX in C64 mode,
+; * make sure you use 'detect_c65();' before using.
+; */
+
+; unsigned char get_c65_speed (void);
+;
+;/* Get the speed of the C65 CPU.
+; *
+; * Possible return values:
+; * SPEED_SLOW  : 1 Mhz mode
+; * SPEED_3X    : 3.5 Mhz mode
+; *
+; * This function does not check for the presence of a C65/C64DX in C64 mode,
+; * make sure you use 'detect_c65();' before using.
+; */
+
+        .export         _set_c65_speed
+        .export         _get_c65_speed
+
+        .include        "accelerator.inc"
+
+_set_c65_speed:
+        tay
+        jsr     activate_new_vic_mode
+        cpy     #SPEED_3X
+        bcs     high_speed
+low_speed:
+        and     #$BF
+store_speed:
+        sta     C65_VICIII_CTRL_B
+        lda     C65_VICIII_CTRL_B
+        jmp     return_c65_speed
+
+high_speed:
+        ora     #$40
+        bne     store_speed
+
+_get_c65_speed:
+        jsr     activate_new_vic_mode
+return_c65_speed:
+        sta     C65_VICIII_KEY
+        and     #$40
+        beq     speed_is_slow
+        lda     #SPEED_3X
+        .byte   $2C
+speed_is_slow:
+        ldx     #$00
+        rts
+
+activate_new_vic_mode:
+        lda     #C65_VICIII_UNLOCK_1
+        sta     C65_VICIII_KEY
+        lda     #C65_VICIII_UNLOCK_2
+        sta     C65_VICIII_KEY
+        lda     C65_VICIII_CTRL_B
+        rts
diff --git a/libsrc/c64/acc_detect_c65.s b/libsrc/c64/acc_detect_c65.s
new file mode 100755
index 000000000..8e9f9b9ec
--- /dev/null
+++ b/libsrc/c64/acc_detect_c65.s
@@ -0,0 +1,55 @@
+;
+; Marco van den Heuvel, 2018-04-27
+;
+
+; unsigned char detect_c65 (void);
+;
+;/* Check for the presence of a C65/C64DX in C64 mode.
+; *
+; * Possible return values:
+; * 0x00  : C65/C64DX in C64 mode not present
+; * 0x01  : C65/C64DX in C64 mode present
+; */
+
+        .export         _detect_c65
+
+        .include        "accelerator.inc"
+
+_detect_c65:
+        ldy     $D000
+
+; Make sure the CPU is not a 65816
+        clc
+        .byte   $E2,$01                ; NOP #$01 on 6510 and 65(S)C02, LDA $(01,S),Y on 65CE02 and 4510, SEP #$01 on 65816
+        lda     #$00
+        tax
+        bcs     not_found              ; carry will be set on 65816
+
+; Make sure the CPU is not a 6510
+        .byte   $1A                    ; NOP on 6510, INA on 65(S)C(E)02
+        beq     not_found
+        txa
+
+; Make sure the CPU is a 65CE02/4510
+        .byte   $A3,$A3                ; NOP NOP on 65(S)C02, LDZ #$A3 on 65CE02 and 4510
+        .byte   $6B                    ; NOP on 65(S)C02, TZA on 65CE02 and 4510
+        cmp     #$A3
+        bne     not_found
+
+; Switch to VICIII mode and check if $D040 is a mirror of $D000
+        ldy     #C65_VICIII_UNLOCK_1
+        sty     C65_VICIII_KEY
+        ldy     #C65_VICIII_UNLOCK_2
+        sty     C65_VICIII_KEY
+        cpy     $D040
+        bne     found
+        inc     $D000
+        cpy     $D040
+        beq     not_found
+
+found:
+        lda     #$01
+not_found:
+        sty     $D000
+        sta     C65_VICIII_KEY
+        rts
diff --git a/testcode/lib/accelerator/Makefile b/testcode/lib/accelerator/Makefile
index e9bd61881..9ff4d96b4 100644
--- a/testcode/lib/accelerator/Makefile
+++ b/testcode/lib/accelerator/Makefile
@@ -1,7 +1,8 @@
 CL ?= cl65
 
 all:	c64-scpu-test.prg c128-scpu-test.prg c64dtv-test.prg \
-	c64-c128-test.prg c128-test.prg chameleon-test.prg
+	c64-c128-test.prg c128-test.prg chameleon-test.prg \
+	c65-test.prg
 
 c64-scpu-test.prg: c64-c128-scpu-test.c
 	$(CL) -t c64 c64-c128-scpu-test.c -o c64-scpu-test.prg
@@ -20,3 +21,6 @@ c128-test.prg: c64-c128-test.c
 
 chameleon-test.prg: chameleon-test.c
 	$(CL) -t c64 chameleon-test.c -o chameleon-test.prg
+
+c65-test.prg: c65-test.c
+	$(CL) -t c64 c65-test.c -o c65-test.prg
diff --git a/testcode/lib/accelerator/c65-test.c b/testcode/lib/accelerator/c65-test.c
new file mode 100644
index 000000000..02e322625
--- /dev/null
+++ b/testcode/lib/accelerator/c65-test.c
@@ -0,0 +1,8 @@
+/* C65/C64DX in C64 mode accelerator test code. */
+
+#define ACC_DETECT      detect_c65
+#define ACC_GET_SPEED   get_c65_speed
+#define ACC_SET_SPEED   set_c65_speed
+#define ACC_NAME        "C65"
+
+#include "turbo-test.c"
-- 
2.39.2