start z80 impl

MCUME_pico/picocpc/cpc.cpp

@@ -1,35 +1,51 @@
 #include "processor/Z80.h"
 #include "roms/rom464.h"
 #include "emuapi.h"
+#include "crtc.h"
+#include "ga.h"
 
-struct { unsigned char R,G,B;} Palette[27] = {
-    { 0, 0, 0},       // Black
-    { 0, 0, 128},     // Blue
-    { 0, 0, 255},     // Bright blue
-    { 128, 0, 0},     // Red
-    { 128, 0, 128},   // Magenta
-    { 128, 0, 255},   // Mauve
-    { 255, 0, 0},     // Bright Red
-    { 255, 0, 128},   // Purple
-    { 255, 0, 255},   // Bright Magenta
-    { 0, 128, 0},     // Green
-    { 0, 128, 128},   // Cyan
-    { 0, 128, 255},   // Sky Blue
-    { 128, 128, 0},   // Yellow
-    { 128, 128, 128}, // White
-    { 128, 128, 255}, // Pastel Blue
-    { 255, 128, 0},   // Orange
-    { 255, 128, 128}, // Pink
-    { 255, 128, 255}, // Pastel Magenta
-    { 0, 255, 0},     // Bright Green
-    { 0, 255, 128},   // Sea Green
-    { 0, 255, 255},   // Bright Cyan
-    { 128, 255, 0},   // Lime
-    { 128, 255, 128}, // Pastel Green 
-    { 128, 255, 255}, // Pastel Cyan
-    { 255, 255, 0},   // Bright Yellow
-    { 255, 255, 128}, // Pastel Yellow
-    { 255, 255, 255}, // Bright White
-};
+/*
+ * The implementations of the Z80 instructions required by the portable Z80 emulator.
+ * These implementations are system-specific.
+*/
+void OutZ80(register word Port, register byte Value)
+{
+    if(!(Port & 0x8000)) write_ga(Port, Value); // The Gate Array is selected when bit 15 is set to 0.
+    if(!(Port & 0x4000)) write_crtc(Port, Value); // The CRTC is selected when bit 14 is set to 0. 
+    return;
+}
 
-// TODO add cpu instance etc.
+byte InZ80(register word Port)
+{
+    if(!(Port & 0x4000)) read_crtc(Port); // The CRTC is selected when bit 14 is set to 0. 
+    return 0xFF;
+}
+
+void WrZ80(register word Addr,register byte Value)
+{
+    return;
+}
+
+byte RdZ80(register word Addr)
+{
+    return 0xFF;
+}
+
+void PatchZ80(register Z80 *R)
+{
+    return;
+}
+
+word LoopZ80(register Z80 *R)
+{
+    return 0xFFFF;
+}
+
+// void JumpZ80(word PC)
+// {
+//     return;
+// }
+
+/*
+ * Non-Z80 stuff.
+*/

MCUME_pico/picocpc/crtc.cpp

@@ -3,5 +3,42 @@
  * video memory addresses to fetch pixel data. 
  * Gate Array works together in sync with CRTC, and is responsible for converting the pixel data in memory 
  * into video signals through an R2R DAC.
- * 
-*/
+*/
+#include "pico.h"
+#include "pico/stdlib.h"
+
+struct Registers {
+    uint8_t HorizontalTotal = 63;
+    uint8_t HorizontalDisplayed = 40;
+    uint8_t HorizontalSyncPosition = 46;
+    uint8_t HorizontalAndVerticalSyncWidths = 142;
+    uint8_t VerticalTotal = 38;
+    uint8_t VerticalTotalAdjust = 0;
+    uint8_t VerticalDisplayed = 25;
+    uint8_t VerticalSyncPosition = 30;
+    uint8_t InterlaceAndSkew = 0;
+    uint8_t MaximumRasterAddress = 7;
+    uint8_t CursorStartRaster = 0;
+    uint8_t CursorEndRaster = 0;
+    uint8_t DisplayStartAddressHigh = 48;
+    uint8_t DisplayStartAddressLow = 0;
+    uint8_t CursorAddressHigh = 0;
+    uint8_t CursorAddressLow = 0;
+    uint8_t LightPenAddressHigh = 0; // Read only
+    uint8_t LightPenAddressLow = 0; // Read only 
+};
+
+void write_crtc(unsigned short address, unsigned short value)
+{
+
+    return;
+}
+
+void read_crtc(unsigned short address)
+{
+    switch(address & 0xFF00)
+    {
+        case 0xBF00: break;
+    }
+    return;
+}

MCUME_pico/picocpc/crtc.h

@@ -0,0 +1,2 @@
+void write_crtc(unsigned short address, unsigned short value);
+void read_crtc(unsigned short address);

MCUME_pico/picocpc/ga.cpp

@@ -3,4 +3,33 @@
  * Gate Array's READY signal is connected to Z80's WAIT input for "memory contention". 
  * This means CPU execution is halted every time Gate Array and CPU accesses the memory at the same time. 
  * The reason for this is that both GA and the CPU share the same address/data bus for memory access.
-*/
+*/
+struct { unsigned char R,G,B;} Palette[27] = {
+    { 0, 0, 0},       // Black
+    { 0, 0, 128},     // Blue
+    { 0, 0, 255},     // Bright blue
+    { 128, 0, 0},     // Red
+    { 128, 0, 128},   // Magenta
+    { 128, 0, 255},   // Mauve
+    { 255, 0, 0},     // Bright Red
+    { 255, 0, 128},   // Purple
+    { 255, 0, 255},   // Bright Magenta
+    { 0, 128, 0},     // Green
+    { 0, 128, 128},   // Cyan
+    { 0, 128, 255},   // Sky Blue
+    { 128, 128, 0},   // Yellow
+    { 128, 128, 128}, // White
+    { 128, 128, 255}, // Pastel Blue
+    { 255, 128, 0},   // Orange
+    { 255, 128, 128}, // Pink
+    { 255, 128, 255}, // Pastel Magenta
+    { 0, 255, 0},     // Bright Green
+    { 0, 255, 128},   // Sea Green
+    { 0, 255, 255},   // Bright Cyan
+    { 128, 255, 0},   // Lime
+    { 128, 255, 128}, // Pastel Green 
+    { 128, 255, 255}, // Pastel Cyan
+    { 255, 255, 0},   // Bright Yellow
+    { 255, 255, 128}, // Pastel Yellow
+    { 255, 255, 255}, // Bright White
+};

MCUME_pico/picocpc/ga.h

@@ -0,0 +1 @@
+void write_ga(unsigned short address, unsigned short value);