From 3f5683b39139bd7f211fd72822c562863014e6cb Mon Sep 17 00:00:00 2001
From: Marco van den Heuvel <blackystardust68@yahoo.com>
Date: Fri, 20 Apr 2018 12:08:28 -0700
Subject: [PATCH] Added C128 in C64 mode accelerator code and documentation.

---
 asminc/accelerator.inc                   |  7 +++
 doc/c64.sgml                             |  3 ++
 doc/funcref.sgml                         | 67 ++++++++++++++++++++++++
 include/accelerator.h                    | 39 ++++++++++++++
 libsrc/c64/acc_c128_speed.s              | 53 +++++++++++++++++++
 libsrc/c64/acc_detect_c128.s             | 33 ++++++++++++
 testcode/lib/accelerator/Makefile        |  4 +-
 testcode/lib/accelerator/c64-c128-test.c |  8 +++
 8 files changed, 213 insertions(+), 1 deletion(-)
 create mode 100755 libsrc/c64/acc_c128_speed.s
 create mode 100755 libsrc/c64/acc_detect_c128.s
 create mode 100755 testcode/lib/accelerator/c64-c128-test.c

diff --git a/asminc/accelerator.inc b/asminc/accelerator.inc
index 1008b49c1..86d27b3f2 100644
--- a/asminc/accelerator.inc
+++ b/asminc/accelerator.inc
@@ -40,3 +40,10 @@ C64DTV_Extended_Regs := $D03F
 
 C64DTV_Slow = $00
 C64DTV_Fast = $03
+
+
+; ---------------------------------------------------------------------------
+; C128 in C64 mode
+
+C128_VICIIE_CLK := $D030
+
diff --git a/doc/c64.sgml b/doc/c64.sgml
index f1e678c72..03a03974c 100644
--- a/doc/c64.sgml
+++ b/doc/c64.sgml
@@ -176,10 +176,13 @@ url="funcref.html" name="function reference"> for declaration and usage.
 
 <itemize>
 <item>detect_c64dtv
+<item>detect_c128
 <item>detect_scpu
 <item>get_c64dtv_speed
+<item>get_c128_speed
 <item>get_scpu_speed
 <item>set_c64dtv_speed
+<item>set_c128_speed
 <item>set_scpu_speed
 </itemize>
 
diff --git a/doc/funcref.sgml b/doc/funcref.sgml
index 268c210fe..17a42b103 100644
--- a/doc/funcref.sgml
+++ b/doc/funcref.sgml
@@ -69,10 +69,13 @@ function.
 
 <itemize>
 <item><ref id="detect_c64dtv" name="detect_c64dtv">
+<item><ref id="detect_c128" name="detect_c128">
 <item><ref id="detect_scpu" name="detect_scpu">
 <item><ref id="get_c64dtv_speed" name="get_c64dtv_speed">
+<item><ref id="get_c128_speed" name="get_c128_speed">
 <item><ref id="get_scpu_speed" name="get_scpu_speed">
 <item><ref id="set_c64dtv_speed" name="set_c64dtv_speed">
+<item><ref id="set_c128_speed" name="set_c64dtv_speed">
 <item><ref id="set_scpu_speed" name="set_scpu_speed">
 </itemize>
 
@@ -2943,6 +2946,26 @@ used in presence of a prototype.
 </quote>
 
 
+<sect1>detect_c128<label id="detect_c128"><p>
+
+<quote>
+<descrip>
+<tag/Function/Check for the presence of a C128 in C64 mode.
+<tag/Header/<tt/<ref id="accelerator.h" name="accelerator.h">/
+<tag/Declaration/<tt/unsigned char detect_c128 (void);/
+<tag/Description/The function returns a 1 if a C128 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_c128_speed" name="get_c128_speed">,
+<ref id="set_c128_speed" name="set_c128_speed">,
+<tag/Example/None.
+</descrip>
+</quote>
+
+
 <sect1>detect_scpu<label id="detect_scpu"><p>
 
 <quote>
@@ -3524,6 +3547,28 @@ header files define constants that can be used to check the return code.
 </quote>
 
 
+<sect1>get_c128_speed<label id="get_c128_speed"><p>
+
+<quote>
+<descrip>
+<tag/Function/Get the current speed of the C128 in C64 mode.
+<tag/Header/<tt/<ref id="accelerator.h" name="accelerator.h">/
+<tag/Declaration/<tt/unsigned char get_c128_speed (void);/
+<tag/Description/The function returns the current speed of the C128 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 C128 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_c128" name="detect_c128">,
+<ref id="set_c128_speed" name="set_c128_speed">,
+<tag/Example/None.
+</descrip>
+</quote>
+
+
 <sect1>get_scpu_speed<label id="get_scpu_speed"><p>
 
 <quote>
@@ -6119,6 +6164,28 @@ clean-up when exitting the program.
 </quote>
 
 
+<sect1>set_c128_speed<label id="set_c128_speed"><p>
+
+<quote>
+<descrip>
+<tag/Function/Set the current speed of a C128 in C64 mode.
+<tag/Header/<tt/<ref id="accelerator.h" name="accelerator.h">/
+<tag/Declaration/<tt/unsigned char __fastcall__ set_c128_speed (unsigned char speed);/
+<tag/Description/The function returns the speed after trying to set the speed of the C128 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 C128 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_c128" name="detect_c128">,
+<ref id="get_c128_speed" name="get_c128_speed">,
+<tag/Example/None.
+</descrip>
+</quote>
+
+
 <sect1>set_scpu_speed<label id="set_scpu_speed"><p>
 
 <quote>
diff --git a/include/accelerator.h b/include/accelerator.h
index 336bbb036..0e3ba6e36 100644
--- a/include/accelerator.h
+++ b/include/accelerator.h
@@ -136,5 +136,44 @@ extern unsigned char detect_c64dtv (void);
  * 0x01  : C64DTV present
  */
 
+
+/* C128 in C64 mode */
+
+extern unsigned char __fastcall__ set_c128_speed (unsigned char speed);
+
+/* Set the speed of the C128 CPU, using SPEED_SLOW will switch to
+ * 1 Mhz (slow) mode, SPEED_2X or SPEED_FAST will switch to 2Mhz (fast) mode.
+ *
+ * Note that any value higher or equal to SPEED_2X 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 C128 in C64 mode,
+ * make sure you use 'detect_c128();' before using.
+ */
+
+extern unsigned char get_c128_speed (void);
+
+/* Get the speed of the C128 CPU.
+ *
+ * Possible return values:
+ * SPEED_SLOW  : Slow mode
+ * SPEED_2X    : Fast mode
+ *
+ * This function does not check for the presence of a C128 in C64 mode,
+ * make sure you use 'detect_c128();' before using.
+ */
+
+extern unsigned char detect_c128 (void);
+
+/* Check for the presence of a C128 in C64 mode.
+ *
+ * Possible return values:
+ * 0x00  : C128 in C64 mode not present
+ * 0x01  : C128 in C64 mode present
+ */
+
 /* End of accelerator.h */
 #endif
+
diff --git a/libsrc/c64/acc_c128_speed.s b/libsrc/c64/acc_c128_speed.s
new file mode 100755
index 000000000..4ec23b1da
--- /dev/null
+++ b/libsrc/c64/acc_c128_speed.s
@@ -0,0 +1,53 @@
+;
+; Marco van den Heuvel, 2018-04-20
+;
+
+; extern unsigned char __fastcall__ set_c128_speed (unsigned char speed);
+;
+;/* Set the speed of the C128 CPU, using SPEED_SLOW will switch to
+; * 1 Mhz (slow) mode, SPEED_2X or SPEED_FAST will switch to 2Mhz (fast) mode.
+; *
+; * Note that any value higher or equal to SPEED_2X 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 C128 in C64 mode,
+; * make sure you use 'detect_c128();' before using.
+; */
+
+; extern unsigned char get_c128_speed (void);
+;
+;/* Get the speed of the C128 CPU.
+; *
+; * Possible return values:
+; * SPEED_SLOW  : Slow mode
+; * SPEED_2X    : Fast mode
+; *
+; * This function does not check for the presence of a C128 in C64 mode,
+; * make sure you use 'detect_c128();' before using.
+; */
+
+        .export         _set_c128_speed
+        .export         _get_c128_speed
+
+        .include        "accelerator.inc"
+
+_set_c128_speed:
+        cmp     #SPEED_2X
+        bcs     high_speed
+store_speed:
+        sta     C128_VICIIE_CLK
+        jmp     _get_c128_speed
+
+high_speed:
+        lda     #$01
+        bne     store_speed
+
+
+_get_c128_speed:
+        lda     C128_VICIIE_CLK
+        and     #$01
+        ldx     #$00
+        rts
+
diff --git a/libsrc/c64/acc_detect_c128.s b/libsrc/c64/acc_detect_c128.s
new file mode 100755
index 000000000..591ff6c59
--- /dev/null
+++ b/libsrc/c64/acc_detect_c128.s
@@ -0,0 +1,33 @@
+;
+; Marco van den Heuvel, 2018-04-20
+;
+
+; unsigned char detect_c128 (void);
+;
+;/* Check for the presence of a C128 in C64 mode.
+; *
+; * Possible return values:
+; * 0x00  : C128 in C64 mode not present
+; * 0x01  : C128 in C64 mode present
+; */
+
+        .export         _detect_c128
+
+        .include        "accelerator.inc"
+
+_detect_c128:
+        lda     #$00
+        tax
+
+; Make sure the CPU is a 8502
+        .byte   $1A                   ; NOP on 8502, INA on 65(S)C(E)02, 4510 and 65816
+        bne     not_found
+
+; Make sure a C128 VICIIe is present
+        ldy     C128_VICIIE_CLK
+        cpy     #$FF
+        beq     not_found
+found:
+        lda     #$01
+not_found:
+        rts
diff --git a/testcode/lib/accelerator/Makefile b/testcode/lib/accelerator/Makefile
index a9fe5f78d..c6423e44f 100644
--- a/testcode/lib/accelerator/Makefile
+++ b/testcode/lib/accelerator/Makefile
@@ -1,6 +1,6 @@
 CL ?= cl65
 
-all: c64-scpu-test.prg c128-scpu-test.prg c64dtv-test.prg
+all: c64-scpu-test.prg c128-scpu-test.prg c64dtv-test.prg c64-c128-test.prg
 
 c64-scpu-test.prg: c64-c128-scpu-test.c
 	$(CL) -t c64 c64-c128-scpu-test.c -o c64-scpu-test.prg
@@ -11,3 +11,5 @@ c128-scpu-test.prg: c64-c128-scpu-test.c
 c64dtv-test.prg: c64dtv-test.c
 	$(CL) -t c64 c64dtv-test.c -o c64dtv-test.prg
 
+c64-c128-test.prg: c64-c128-test.c
+	$(CL) -t c64 c64-c128-test.c -o c64-c128-test.prg
diff --git a/testcode/lib/accelerator/c64-c128-test.c b/testcode/lib/accelerator/c64-c128-test.c
new file mode 100755
index 000000000..fd20a665e
--- /dev/null
+++ b/testcode/lib/accelerator/c64-c128-test.c
@@ -0,0 +1,8 @@
+/* C128 in C64 mode accelerator test code. */
+
+#define ACC_DETECT      detect_c128
+#define ACC_GET_SPEED   get_c128_speed
+#define ACC_SET_SPEED   set_c128_speed
+#define ACC_NAME        "C128 in C64 mode"
+
+#include "turbo-test.c"
-- 
2.39.5