Added a VIC 20 target. Added CONIO support for VIC 20.

src/main/kc/include/conio.h

@@ -2,7 +2,7 @@
 // Implements similar functions as conio.h from CC65 for compatibility
 // See https://github.com/cc65/cc65/blob/master/include/conio.h
 //
-// Currently only the C64 and PLUS4 platform is supported
+// Currently C64/PLUS4/VIC20 platforms are supported
 
 
 // clears the screen and moves the cursor to the upper left-hand corner of the screen.

src/main/kc/include/mos6522.h

@@ -0,0 +1,39 @@
+// MOS 6522 Versatile Interface Adapter (VIA) 
+// Used in VIC 20 and 1541
+// https://en.wikipedia.org/wiki/MOS_Technology_6522
+// http://archive.6502.org/datasheets/mos_6522_preliminary_nov_1977.pdf
+
+struct MOS6522_VIA {
+    // Port B
+    char PORT_B;
+    // Port A
+    char PORT_A;
+    // Port B data direction register.
+    char PORT_B_DDR;
+    // Port A data direction register.
+    char PORT_A_DDR;
+    // Timer 1 low byte
+    char TIMER1_LOW;
+    // Timer 1 high byte
+    char TIMER1_HIGH;
+    // Timer 1 latch low byte
+    char TIMER1_LATCH_LOW;
+    // Timer 1 latch high byte
+    char TIMER1_LATCH_HIGH;
+    // Timer 2 low byte
+    char TIMER2_LOW;
+    // Timer 2 high byte
+    char TIMER2_HIGH;
+    // Shift Register
+    char SHIFT;
+    // Auxiliary Control Register
+    char AUX_CONTROL;
+    // Peripheral Control Register
+    char PERIPHERAL_CONTROL;
+    // Interrupt Flag Register
+    char INTERRUPT_FLAG;
+    // Interrupt Enable Register
+    char INTERRUPT_ENABLE;
+    // Port A Output (no handshake)
+    char PORT_A_OUTPUT;
+};

src/main/kc/include/mos6561.h

@@ -0,0 +1,64 @@
+// MOS 6560/6561 VIDEO INTERFACE CHIP
+// Used in VIC 20
+// http://archive.6502.org/datasheets/mos_6560_6561_vic.pdf
+
+struct MOS6561_VIC {
+    // Screen Origin X-coordinate
+    //   bits 0-6: horizontal centering
+    //   bit 7: sets interlace scan
+    char ORIGIN_X;
+    // Screen Origin Y-coordinate
+    //   bit 0-7: vertical centering
+    char ORIGIN_Y;
+    // Number of Screen Columns
+    //   bits 0-6: Number of columns
+    //   bit 7: Upper bit of video matrix address (also controls address of COLOR RAM)
+    char MATRIX_COLUMNS;
+    //   Number of Screen Rows
+    //   bits 1-6: set ol rows
+    //   bit 7:  sets or 16 chars
+    char MATRIX_ROWS;
+    //   The Raster Line
+    //   bits 0-7: Current TV raster beam line
+    char RASTER;
+    // Character and Screen Address
+    //   bits 0-3: start of character memory (default 0)
+    //             ROM: 0000: 0x8000, 0001: 0x8400, 0010: 0x8800, 0011: 0x8c00
+    //             RAM: 1000: 0x0000, 1001: unavail, 1010: unavail, 1011: unavail
+    //             RAM: 1100: 0x1000, 1101: 0x1400, 1110: 0x1800, 1111: 0x1c00
+    //   bits 4-7: is rest of video matrix address (default F)
+    char MEMORY;
+    // Lightpen X position
+    // bits 0-7: horizontal position of light pen
+    char LIGHTPEN_X;
+    // Lightpen Y position
+    // bits 0-7: vertical position of light pen
+    char LIGHTPEN_Y;
+    // Paddle X position
+    // bit 0-7: Digitized value of paddle X
+    char PADDLE_X;
+    // Paddle Y position
+    // bit 0-7: Digitized value oi paddle Y
+    char PADDLE_Y;
+    // Sound Voice 1 (low) frequency
+    // Frequency for oscillator 1 (low) (on: 128-255)
+    char CH1_FREQ;
+    // Sound Voice 2 (medium) frequency
+    // Frequency for oscillator 1 (medium) (on: 128-255)
+    char CH2_FREQ;
+    // Sound Voice 3 (high) frequency
+    // Frequency for oscillator 1 (high) (on: 128-255)
+    char CH3_FREQ;
+    // Sound Voice 4 (noise) frequency
+    // Frequency of noise source
+    char CH4_FREQ;
+    // Sound Volume and auxiliary color information
+    //   bit 0-3: sets volume of all sound
+    //   bits 4-7: are auxiliary color information
+    char VOLUME_COLOR;
+    // Screen and border color register
+    //   bits 4-7: background color
+    //   bit 3: inverted or normal mode
+    //   bits 0-2: border color
+    char BORDER_BACKGROUND_COLOR;
+};

src/main/kc/include/vic20.h

@@ -0,0 +1,42 @@
+// Commodore VIC 20 registers and memory layout
+// http://sleepingelephant.com/denial/wiki/index.php?title=Memory_Map
+// http://www.zimmers.net/anonftp/pub/cbm/vic20/manuals/VIC-20_Programmers_Reference_Guide_1st_Edition_6th_Printing.pdf
+
+#include <mos6561.h>
+#include <mos6522.h>
+
+// Default address of screen color matrix
+char * const DEFAULT_COLORRAM = 0x9600;
+// Address of screen color matrix if bit 7 of $9002 is 1
+char * const ALTERNATIVE_COLORRAM = 0x9400;
+// Default address of screen character matrix
+char * const DEFAULT_SCREEN = 0x1e00;
+
+// The address of the CHARGEN character set
+char * const CHARGEN = 0x8000;
+
+// The MOS 6560/6561 VIC Video Interface Chip
+struct MOS6561_VIC * const VIC = 0x9000;
+
+// The VIA#1: User port, RS-232, Joystick, Lightpen, Cassette
+struct MOS6522_VIA * const VIA1 = 0x9110;
+// The VIA#2: Keyboard, Joystick, Cassette
+struct MOS6522_VIA * const VIA2 = 0x9120;
+
+// The colors of the VIC 20
+const char BLACK = 0x0;
+const char WHITE = 0x1;
+const char RED = 0x2;
+const char CYAN = 0x3;
+const char PURPLE = 0x4;
+const char GREEN = 0x5;
+const char BLUE = 0x6;
+const char YELLOW = 0x7;
+const char ORANGE = 0x8;
+const char LIGHT_ORANGE = 0x9;
+const char PINK = 0xa;
+const char LIGHT_CYAN= 0xb;
+const char LIGHT_PURPLE = 0xc;
+const char LIGHT_GREEN = 0xd;
+const char LIGHT_BLUE = 0xe;
+const char LIGHT_YELLOW = 0xf;

src/main/kc/lib/conio.c

@@ -2,7 +2,7 @@
 // Implements similar functions as conio.h from CC65 for compatibility
 // See https://github.com/cc65/cc65/blob/master/include/conio.h
 //
-// Currently only the C64/PLUS4 platforms are supported
+// Currently C64/PLUS4/VIC20 platforms are supported
 #include <conio.h>
 #include <string.h>
 
@@ -18,21 +18,35 @@
     char * const CONIO_SCREEN_TEXT = 0x0400;
     // The color screen address
     char * const CONIO_SCREEN_COLORS = 0xd800;
-    // The background color register address
-    char * const CONIO_BGCOLOR = 0xd021;
-    // The border color register address
-    char * const CONIO_BORDERCOLOR = 0xd020;
     // The default text color
     const char CONIO_TEXTCOLOR_DEFAULT = 0xe;
 
     // Return true if there's a key waiting, return false if not
     unsigned char kbhit (void) {
         // CIA#1 Port A: keyboard matrix columns and joystick #2
-        char* const CONIO_CIA1_PORT_A = 0xdc00;
+        char* const CIA1_PORT_A = 0xdc00;
         // CIA#1 Port B: keyboard matrix rows and joystick #1.
-        char* const CONIO_CIA1_PORT_B = 0xdc01;
-        *CONIO_CIA1_PORT_A = 0;
-        return ~*CONIO_CIA1_PORT_B;
+        char* const CIA1_PORT_B = 0xdc01;
+        *CIA1_PORT_A = 0;
+        return ~*CIA1_PORT_B;
+    }
+
+    // Set the color for the background. The old color setting is returned.
+    unsigned char bgcolor(unsigned char color) {
+        // The background color register address
+        char * const CONIO_BGCOLOR = 0xd021;
+        char old = *CONIO_BGCOLOR;
+        *CONIO_BGCOLOR = color;
+        return old;
+    }
+
+    // Set the color for the border. The old color setting is returned.
+    unsigned char bordercolor(unsigned char color) {
+        // The border color register address
+        char * const CONIO_BORDERCOLOR = 0xd020;
+        char old = *CONIO_BORDERCOLOR;
+        *CONIO_BORDERCOLOR = color;
+        return old;
     }
 
 #elif defined(__PLUS4__)
@@ -50,10 +64,6 @@
     char * const CONIO_SCREEN_TEXT = DEFAULT_SCREEN;
     // The color screen address
     char * const CONIO_SCREEN_COLORS = DEFAULT_COLORRAM;
-    // The background color register address
-    char * const CONIO_BGCOLOR = &TED->BG_COLOR;
-    // The border color register address
-    char * const CONIO_BORDERCOLOR = &TED->BORDER_COLOR;
     // The default text color
     const char CONIO_TEXTCOLOR_DEFAULT = 0;
 
@@ -69,6 +79,60 @@
         return ~TED->KEYBOARD_INPUT;
     }
 
+    // Set the color for the background. The old color setting is returned.
+    unsigned char bgcolor(unsigned char color) {
+        char old = TED->BG_COLOR;
+        TED->BG_COLOR = color;
+        return old;
+    }
+
+    // Set the color for the border. The old color setting is returned.
+    unsigned char bordercolor(unsigned char color) {
+        char old = TED->BORDER_COLOR;
+        TED->BORDER_COLOR = color;
+        return old;
+    }
+
+#elif defined(__VIC20__)
+
+    #include <vic20.h>
+
+    // The screen width
+    #define CONIO_WIDTH 22
+    // The screen height
+    #define CONIO_HEIGHT 23
+    // The screen bytes
+    #define CONIO_BYTES CONIO_HEIGHT*CONIO_WIDTH
+
+    // The text screen address
+    char * const CONIO_SCREEN_TEXT = DEFAULT_SCREEN;
+    // The color screen address
+    char * const CONIO_SCREEN_COLORS = DEFAULT_COLORRAM;
+    // The default text color
+    const char CONIO_TEXTCOLOR_DEFAULT = BLUE;
+
+    // Return true if there's a key waiting, return false if not
+    unsigned char kbhit (void) {
+        // Read all keyboard matrix rows
+        VIA2->PORT_B = 0x00;
+        // Read the keyboard input
+        return ~VIA2->PORT_A;
+    }
+
+    // Set the color for the background. The old color setting is returned.
+    unsigned char bgcolor(unsigned char color) {
+        char old = VIC->BORDER_BACKGROUND_COLOR;
+        VIC->BORDER_BACKGROUND_COLOR = old&0x0f|(color<<4);
+        return old>>4;
+    }
+
+    // Set the color for the border. The old color setting is returned.
+    unsigned char bordercolor(unsigned char color) {
+        char old = VIC->BORDER_BACKGROUND_COLOR;
+        VIC->BORDER_BACKGROUND_COLOR = old&0xf8|color;
+        return old&0x07;
+    }
+
 #else
 // #error "Target platform does not support conio.h"
 #endif
@@ -240,20 +304,6 @@ unsigned char textcolor(unsigned char color) {
     return old;
 }
 
-// Set the color for the background. The old color setting is returned.
-unsigned char bgcolor(unsigned char color) {
-    char old = *CONIO_BGCOLOR;
-    *CONIO_BGCOLOR = color;
-    return old;
-}
-
-// Set the color for the border. The old color setting is returned.
-unsigned char bordercolor(unsigned char color) {
-    char old = *CONIO_BORDERCOLOR;
-    *CONIO_BORDERCOLOR = color;
-    return old;
-}
-
 // If onoff is 1, a cursor is displayed when waiting for keyboard input.
 // If onoff is 0, the cursor is hidden when waiting for keyboard input.
 // The function returns the old cursor setting.

src/main/kc/target/vic20.ld

@@ -0,0 +1,9 @@
+.file [name="%O.prg", type="prg", segments="Program"]
+.segmentdef Program [segments="Basic, Code, Data"]
+.segmentdef Basic [start=$1001]
+.segmentdef Code [start=$100e]
+.segmentdef Data [startAfter="Code"]
+.segment Basic
+:BasicUpstart(%E)
+.segment Code
+

src/main/kc/target/vic20.tgt

@@ -0,0 +1,8 @@
+{
+    "link": "vic20.ld",
+    "cpu": "MOS6502X",
+    "emulator": "xvic",
+    "defines": {
+        "__VIC20__": 1
+    }
+}

src/main/kc/target/vic20basic.ld

@@ -0,0 +1,3 @@
+.pc = $1001 "Basic"
+:BasicUpstart(%E)
+.pc = %P "Program"

src/main/kc/target/vic20basic.tgt

@@ -0,0 +1,8 @@
+{
+    "link": "vic20basic.ld",
+    "cpu": "MOS6502X",
+    "emulator": "xvic",
+    "defines": {
+        "__VIC20__": 1
+    }
+}

src/test/java/dk/camelot64/kickc/test/TestPrograms.java

@@ -44,6 +44,11 @@ public class TestPrograms {
    public TestPrograms() {
    }
 
+   @Test
+   public void testVic20Simple() throws IOException, URISyntaxException {
+      compileAndCompare("vic20-simple.c");
+   }
+
    @Test
    public void testPlus4KeyboardTest() throws IOException, URISyntaxException {
       compileAndCompare("plus4-keyboard-test.c");

src/test/kc/vic20-simple.c

@@ -0,0 +1,12 @@
+// Trivial VIC 20 program
+#pragma target(vic20)
+#include <vic20.h>
+
+char MESSAGE[] = "hello world!";
+
+void main() {
+    for(char i=0; MESSAGE[i]; i++) {
+        DEFAULT_SCREEN[i] = MESSAGE[i];
+        DEFAULT_COLORRAM[i] = RED;
+    }
+}

src/test/ref/complex/polygon/polygon.asm

@@ -882,14 +882,14 @@ irq_bottom_2: {
 // Return true if there's a key waiting, return false if not
 kbhit: {
     // CIA#1 Port A: keyboard matrix columns and joystick #2
-    .label CONIO_CIA1_PORT_A = $dc00
+    .label CIA1_PORT_A = $dc00
     // CIA#1 Port B: keyboard matrix rows and joystick #1.
-    .label CONIO_CIA1_PORT_B = $dc01
-    // *CONIO_CIA1_PORT_A = 0
+    .label CIA1_PORT_B = $dc01
+    // *CIA1_PORT_A = 0
     lda #0
-    sta CONIO_CIA1_PORT_A
-    // ~*CONIO_CIA1_PORT_B
-    lda CONIO_CIA1_PORT_B
+    sta CIA1_PORT_A
+    // ~*CIA1_PORT_B
+    lda CIA1_PORT_B
     eor #$ff
     // }
     rts

src/test/ref/complex/polygon/polygon.cfg

@@ -448,8 +448,8 @@ irq_bottom_2::@1: scope:[irq_bottom_2]  from irq_bottom_2::@4
 
 (byte()) kbhit()
 kbhit: scope:[kbhit]  from irq_bottom_2
-  [219] *((const nomodify byte*) kbhit::CONIO_CIA1_PORT_A) ← (byte) 0
-  [220] (byte) kbhit::return#0 ← ~ *((const nomodify byte*) kbhit::CONIO_CIA1_PORT_B)
+  [219] *((const nomodify byte*) kbhit::CIA1_PORT_A) ← (byte) 0
+  [220] (byte) kbhit::return#0 ← ~ *((const nomodify byte*) kbhit::CIA1_PORT_B)
   to:kbhit::@return
 kbhit::@return: scope:[kbhit]  from kbhit
   [221] return 

src/test/ref/complex/polygon/polygon.log

@@ -88,11 +88,11 @@ clock_start: scope:[clock_start]  from main::@8
 clock_start::@return: scope:[clock_start]  from clock_start
   return 
   to:@return
-$$
+
 (byte()) kbhit()
 kbhit: scope:[kbhit]  from irq_bottom_2
-  *((const nomodify byte*) kbhit::CONIO_CIA1_PORT_A) ← (number) 0
-  (byte~) kbhit::$0 ← ~ *((const nomodify byte*) kbhit::CONIO_CIA1_PORT_B)
+  *((const nomodify byte*) kbhit::CIA1_PORT_A) ← (number) 0
+  (byte~) kbhit::$0 ← ~ *((const nomodify byte*) kbhit::CIA1_PORT_B)
   (byte) kbhit::return#0 ← (byte~) kbhit::$0
   to:kbhit::@return
 kbhit::@return: scope:[kbhit]  from kbhit
@@ -1321,8 +1321,8 @@ interrupt(KERNEL_KEYBOARD)(void()) irq_bottom_2()
 (byte()) kbhit()
 (byte~) kbhit::$0
 (label) kbhit::@return
-(const nomodify byte*) kbhit::CONIO_CIA1_PORT_A = (byte*)(number) $dc00
-(const nomodify byte*) kbhit::CONIO_CIA1_PORT_B = (byte*)(number) $dc01
+(const nomodify byte*) kbhit::CIA1_PORT_A = (byte*)(number) $dc00
+(const nomodify byte*) kbhit::CIA1_PORT_B = (byte*)(number) $dc01
 (byte) kbhit::return
 (byte) kbhit::return#0
 (byte) kbhit::return#1
@@ -2073,7 +2073,7 @@ Adding number conversion cast (unumber) 0 in (bool~) memset::$0 ← (word) memse
 Adding number conversion cast (unumber) $ffffffff in (number~) clock::$0 ← (number) $ffffffff - *((const nomodify dword*) CIA2_TIMER_AB)
 Adding number conversion cast (unumber) clock::$0 in (number~) clock::$0 ← (unumber)(number) $ffffffff - *((const nomodify dword*) CIA2_TIMER_AB)
 Adding number conversion cast (unumber) $ffffffff in *((const nomodify dword*) CIA2_TIMER_AB) ← (number) $ffffffff
-Adding number conversion cast (unumber) 0 in *((const nomodify byte*) kbhit::CONIO_CIA1_PORT_A) ← (number) 0
+Adding number conversion cast (unumber) 0 in *((const nomodify byte*) kbhit::CIA1_PORT_A) ← (number) 0
 Adding number conversion cast (unumber) $3fff in (number~) toD0181_$0 ← (word~) toD0181_$7 & (number) $3fff
 Adding number conversion cast (unumber) toD0181_$0 in (number~) toD0181_$0 ← (word~) toD0181_$7 & (unumber)(number) $3fff
 Adding number conversion cast (unumber) 4 in (number~) toD0181_$1 ← (unumber~) toD0181_$0 * (number) 4
@@ -2205,7 +2205,7 @@ Adding number conversion cast (unumber) 1 in (byte) sgn_u8::return#3 ← (number
 Successful SSA optimization PassNAddNumberTypeConversions
 Inlining cast (byte*) memset::dst#0 ← (byte*)(void*) memset::str#5
 Inlining cast *((const nomodify dword*) CIA2_TIMER_AB) ← (unumber)(number) $ffffffff
-Inlining cast *((const nomodify byte*) kbhit::CONIO_CIA1_PORT_A) ← (unumber)(number) 0
+Inlining cast *((const nomodify byte*) kbhit::CIA1_PORT_A) ← (unumber)(number) 0
 Inlining cast (word) memset::num#0 ← (unumber)(number) $28*(number) $19
 Inlining cast (byte) memset::c#1 ← (unumber)(number) 0
 Inlining cast (word) memset::num#1 ← (unumber)(number) $28*(number) $19
@@ -3608,8 +3608,8 @@ irq_bottom_2::@1: scope:[irq_bottom_2]  from irq_bottom_2::@4
 
 (byte()) kbhit()
 kbhit: scope:[kbhit]  from irq_bottom_2
-  [219] *((const nomodify byte*) kbhit::CONIO_CIA1_PORT_A) ← (byte) 0
-  [220] (byte) kbhit::return#0 ← ~ *((const nomodify byte*) kbhit::CONIO_CIA1_PORT_B)
+  [219] *((const nomodify byte*) kbhit::CIA1_PORT_A) ← (byte) 0
+  [220] (byte) kbhit::return#0 ← ~ *((const nomodify byte*) kbhit::CIA1_PORT_B)
   to:kbhit::@return
 kbhit::@return: scope:[kbhit]  from kbhit
   [221] return 
@@ -5638,16 +5638,16 @@ irq_bottom_2: {
 // Return true if there's a key waiting, return false if not
 kbhit: {
     // CIA#1 Port A: keyboard matrix columns and joystick #2
-    .label CONIO_CIA1_PORT_A = $dc00
+    .label CIA1_PORT_A = $dc00
     // CIA#1 Port B: keyboard matrix rows and joystick #1.
-    .label CONIO_CIA1_PORT_B = $dc01
+    .label CIA1_PORT_B = $dc01
     .label return = $5d
     .label return_1 = $5b
-    // [219] *((const nomodify byte*) kbhit::CONIO_CIA1_PORT_A) ← (byte) 0 -- _deref_pbuc1=vbuc2 
+    // [219] *((const nomodify byte*) kbhit::CIA1_PORT_A) ← (byte) 0 -- _deref_pbuc1=vbuc2 
     lda #0
-    sta CONIO_CIA1_PORT_A
-    // [220] (byte) kbhit::return#0 ← ~ *((const nomodify byte*) kbhit::CONIO_CIA1_PORT_B) -- vbuz1=_bnot__deref_pbuc1 
-    lda CONIO_CIA1_PORT_B
+    sta CIA1_PORT_A
+    // [220] (byte) kbhit::return#0 ← ~ *((const nomodify byte*) kbhit::CIA1_PORT_B) -- vbuz1=_bnot__deref_pbuc1 
+    lda CIA1_PORT_B
     eor #$ff
     sta.z return
     jmp __breturn
@@ -5853,8 +5853,8 @@ Statement [214] *((byte*)(const nomodify struct MOS6569_VICII*) VICII+(const byt
 Statement [215] *((byte*)(const nomodify struct MOS6569_VICII*) VICII+(const byte) OFFSET_STRUCT_MOS6569_VICII_RASTER) ← (const nomodify byte) BORDER_YPOS_BOTTOM-(byte) 8 [ ] (  [ ] { }  ) always clobbers reg byte a 
 Statement [216] *((const nomodify void()**) KERNEL_IRQ) ← &interrupt(KERNEL_MIN)(void()) irq_bottom_1() [ ] (  [ ] { }  ) always clobbers reg byte a 
 Statement [218] *((byte*)(const nomodify struct MOS6569_VICII*) VICII+(const byte) OFFSET_STRUCT_MOS6569_VICII_MEMORY) ← (volatile byte) canvas_show_memory [ ] (  [ ] { }  ) always clobbers reg byte a 
-Statement [219] *((const nomodify byte*) kbhit::CONIO_CIA1_PORT_A) ← (byte) 0 [ ] ( kbhit:207 [ canvas_show_memory ] { { kbhit::return#0 = kbhit::return#2 } }  ) always clobbers reg byte a 
-Statement [220] (byte) kbhit::return#0 ← ~ *((const nomodify byte*) kbhit::CONIO_CIA1_PORT_B) [ kbhit::return#0 ] ( kbhit:207 [ canvas_show_memory kbhit::return#0 ] { { kbhit::return#0 = kbhit::return#2 } }  ) always clobbers reg byte a 
+Statement [219] *((const nomodify byte*) kbhit::CIA1_PORT_A) ← (byte) 0 [ ] ( kbhit:207 [ canvas_show_memory ] { { kbhit::return#0 = kbhit::return#2 } }  ) always clobbers reg byte a 
+Statement [220] (byte) kbhit::return#0 ← ~ *((const nomodify byte*) kbhit::CIA1_PORT_B) [ kbhit::return#0 ] ( kbhit:207 [ canvas_show_memory kbhit::return#0 ] { { kbhit::return#0 = kbhit::return#2 } }  ) always clobbers reg byte a 
 Statement [222] *((byte*)(const nomodify struct MOS6569_VICII*) VICII+(const byte) OFFSET_STRUCT_MOS6569_VICII_BORDER_COLOR) ← (const nomodify byte) DARK_GREY [ ] (  [ ] { }  ) always clobbers reg byte a 
 Statement [224] *((byte*)(const nomodify struct MOS6569_VICII*) VICII+(const byte) OFFSET_STRUCT_MOS6569_VICII_MEMORY) ← (const byte) irq_bottom_1::toD0181_return#0 [ ] (  [ ] { }  ) always clobbers reg byte a 
 Statement [225] *((byte*)(const nomodify struct MOS6569_VICII*) VICII+(const byte) OFFSET_STRUCT_MOS6569_VICII_IRQ_STATUS) ← (const nomodify byte) IRQ_RASTER [ ] (  [ ] { }  ) always clobbers reg byte a 
@@ -5955,8 +5955,8 @@ Statement [214] *((byte*)(const nomodify struct MOS6569_VICII*) VICII+(const byt
 Statement [215] *((byte*)(const nomodify struct MOS6569_VICII*) VICII+(const byte) OFFSET_STRUCT_MOS6569_VICII_RASTER) ← (const nomodify byte) BORDER_YPOS_BOTTOM-(byte) 8 [ ] (  [ ] { }  ) always clobbers reg byte a 
 Statement [216] *((const nomodify void()**) KERNEL_IRQ) ← &interrupt(KERNEL_MIN)(void()) irq_bottom_1() [ ] (  [ ] { }  ) always clobbers reg byte a 
 Statement [218] *((byte*)(const nomodify struct MOS6569_VICII*) VICII+(const byte) OFFSET_STRUCT_MOS6569_VICII_MEMORY) ← (volatile byte) canvas_show_memory [ ] (  [ ] { }  ) always clobbers reg byte a 
-Statement [219] *((const nomodify byte*) kbhit::CONIO_CIA1_PORT_A) ← (byte) 0 [ ] ( kbhit:207 [ canvas_show_memory ] { { kbhit::return#0 = kbhit::return#2 } }  ) always clobbers reg byte a 
-Statement [220] (byte) kbhit::return#0 ← ~ *((const nomodify byte*) kbhit::CONIO_CIA1_PORT_B) [ kbhit::return#0 ] ( kbhit:207 [ canvas_show_memory kbhit::return#0 ] { { kbhit::return#0 = kbhit::return#2 } }  ) always clobbers reg byte a 
+Statement [219] *((const nomodify byte*) kbhit::CIA1_PORT_A) ← (byte) 0 [ ] ( kbhit:207 [ canvas_show_memory ] { { kbhit::return#0 = kbhit::return#2 } }  ) always clobbers reg byte a 
+Statement [220] (byte) kbhit::return#0 ← ~ *((const nomodify byte*) kbhit::CIA1_PORT_B) [ kbhit::return#0 ] ( kbhit:207 [ canvas_show_memory kbhit::return#0 ] { { kbhit::return#0 = kbhit::return#2 } }  ) always clobbers reg byte a 
 Statement [222] *((byte*)(const nomodify struct MOS6569_VICII*) VICII+(const byte) OFFSET_STRUCT_MOS6569_VICII_BORDER_COLOR) ← (const nomodify byte) DARK_GREY [ ] (  [ ] { }  ) always clobbers reg byte a 
 Statement [224] *((byte*)(const nomodify struct MOS6569_VICII*) VICII+(const byte) OFFSET_STRUCT_MOS6569_VICII_MEMORY) ← (const byte) irq_bottom_1::toD0181_return#0 [ ] (  [ ] { }  ) always clobbers reg byte a 
 Statement [225] *((byte*)(const nomodify struct MOS6569_VICII*) VICII+(const byte) OFFSET_STRUCT_MOS6569_VICII_IRQ_STATUS) ← (const nomodify byte) IRQ_RASTER [ ] (  [ ] { }  ) always clobbers reg byte a 
@@ -7524,14 +7524,14 @@ irq_bottom_2: {
 // Return true if there's a key waiting, return false if not
 kbhit: {
     // CIA#1 Port A: keyboard matrix columns and joystick #2
-    .label CONIO_CIA1_PORT_A = $dc00
+    .label CIA1_PORT_A = $dc00
     // CIA#1 Port B: keyboard matrix rows and joystick #1.
-    .label CONIO_CIA1_PORT_B = $dc01
-    // [219] *((const nomodify byte*) kbhit::CONIO_CIA1_PORT_A) ← (byte) 0 -- _deref_pbuc1=vbuc2 
+    .label CIA1_PORT_B = $dc01
+    // [219] *((const nomodify byte*) kbhit::CIA1_PORT_A) ← (byte) 0 -- _deref_pbuc1=vbuc2 
     lda #0
-    sta CONIO_CIA1_PORT_A
-    // [220] (byte) kbhit::return#0 ← ~ *((const nomodify byte*) kbhit::CONIO_CIA1_PORT_B) -- vbuaa=_bnot__deref_pbuc1 
-    lda CONIO_CIA1_PORT_B
+    sta CIA1_PORT_A
+    // [220] (byte) kbhit::return#0 ← ~ *((const nomodify byte*) kbhit::CIA1_PORT_B) -- vbuaa=_bnot__deref_pbuc1 
+    lda CIA1_PORT_B
     eor #$ff
     jmp __breturn
     // kbhit::@return
@@ -8017,8 +8017,8 @@ interrupt(KERNEL_KEYBOARD)(void()) irq_bottom_2()
 (byte*) irq_bottom_2::toD0181_screen
 (byte()) kbhit()
 (label) kbhit::@return
-(const nomodify byte*) kbhit::CONIO_CIA1_PORT_A = (byte*) 56320
-(const nomodify byte*) kbhit::CONIO_CIA1_PORT_B = (byte*) 56321
+(const nomodify byte*) kbhit::CIA1_PORT_A = (byte*) 56320
+(const nomodify byte*) kbhit::CIA1_PORT_B = (byte*) 56321
 (byte) kbhit::return
 (byte) kbhit::return#0 reg byte a 4.333333333333333
 (byte) kbhit::return#2 reg byte a 4.0
@@ -9648,16 +9648,16 @@ irq_bottom_2: {
 // Return true if there's a key waiting, return false if not
 kbhit: {
     // CIA#1 Port A: keyboard matrix columns and joystick #2
-    .label CONIO_CIA1_PORT_A = $dc00
+    .label CIA1_PORT_A = $dc00
     // CIA#1 Port B: keyboard matrix rows and joystick #1.
-    .label CONIO_CIA1_PORT_B = $dc01
-    // *CONIO_CIA1_PORT_A = 0
-    // [219] *((const nomodify byte*) kbhit::CONIO_CIA1_PORT_A) ← (byte) 0 -- _deref_pbuc1=vbuc2 
+    .label CIA1_PORT_B = $dc01
+    // *CIA1_PORT_A = 0
+    // [219] *((const nomodify byte*) kbhit::CIA1_PORT_A) ← (byte) 0 -- _deref_pbuc1=vbuc2 
     lda #0
-    sta CONIO_CIA1_PORT_A
-    // ~*CONIO_CIA1_PORT_B
-    // [220] (byte) kbhit::return#0 ← ~ *((const nomodify byte*) kbhit::CONIO_CIA1_PORT_B) -- vbuaa=_bnot__deref_pbuc1 
-    lda CONIO_CIA1_PORT_B
+    sta CIA1_PORT_A
+    // ~*CIA1_PORT_B
+    // [220] (byte) kbhit::return#0 ← ~ *((const nomodify byte*) kbhit::CIA1_PORT_B) -- vbuaa=_bnot__deref_pbuc1 
+    lda CIA1_PORT_B
     eor #$ff
     // kbhit::@return
     // }

src/test/ref/complex/polygon/polygon.sym

@@ -192,8 +192,8 @@ interrupt(KERNEL_KEYBOARD)(void()) irq_bottom_2()
 (byte*) irq_bottom_2::toD0181_screen
 (byte()) kbhit()
 (label) kbhit::@return
-(const nomodify byte*) kbhit::CONIO_CIA1_PORT_A = (byte*) 56320
-(const nomodify byte*) kbhit::CONIO_CIA1_PORT_B = (byte*) 56321
+(const nomodify byte*) kbhit::CIA1_PORT_A = (byte*) 56320
+(const nomodify byte*) kbhit::CIA1_PORT_B = (byte*) 56321
 (byte) kbhit::return
 (byte) kbhit::return#0 reg byte a 4.333333333333333
 (byte) kbhit::return#2 reg byte a 4.0

src/test/ref/examples/conio/nacht-screen.asm

@@ -31,10 +31,6 @@
   .label CONIO_SCREEN_TEXT = $400
   // The color screen address
   .label CONIO_SCREEN_COLORS = $d800
-  // The background color register address
-  .label CONIO_BGCOLOR = $d021
-  // The border color register address
-  .label CONIO_BORDERCOLOR = $d020
   .label VIC_MEMORY = $d018
   .label conio_cursor_x = 9
   .label conio_cursor_y = $a
@@ -172,14 +168,14 @@ clrscr: {
 // Return true if there's a key waiting, return false if not
 kbhit: {
     // CIA#1 Port A: keyboard matrix columns and joystick #2
-    .label CONIO_CIA1_PORT_A = $dc00
+    .label CIA1_PORT_A = $dc00
     // CIA#1 Port B: keyboard matrix rows and joystick #1.
-    .label CONIO_CIA1_PORT_B = $dc01
-    // *CONIO_CIA1_PORT_A = 0
+    .label CIA1_PORT_B = $dc01
+    // *CIA1_PORT_A = 0
     lda #0
-    sta CONIO_CIA1_PORT_A
-    // ~*CONIO_CIA1_PORT_B
-    lda CONIO_CIA1_PORT_B
+    sta CIA1_PORT_A
+    // ~*CIA1_PORT_B
+    lda CIA1_PORT_B
     eor #$ff
     // }
     rts
@@ -839,6 +835,8 @@ cursor: {
 }
 // Set the color for the background. The old color setting is returned.
 bgcolor: {
+    // The background color register address
+    .label CONIO_BGCOLOR = $d021
     // *CONIO_BGCOLOR = color
     lda #COLOR_BLACK
     sta CONIO_BGCOLOR
@@ -847,6 +845,8 @@ bgcolor: {
 }
 // Set the color for the border. The old color setting is returned.
 bordercolor: {
+    // The border color register address
+    .label CONIO_BORDERCOLOR = $d020
     // *CONIO_BORDERCOLOR = color
     lda #COLOR_BLACK
     sta CONIO_BORDERCOLOR

src/test/ref/examples/conio/nacht-screen.cfg

@@ -82,8 +82,8 @@ clrscr::@4: scope:[clrscr]  from clrscr::@3
 
 (byte()) kbhit()
 kbhit: scope:[kbhit]  from main::@1
-  [40] *((const nomodify byte*) kbhit::CONIO_CIA1_PORT_A) ← (byte) 0
-  [41] (byte) kbhit::return#0 ← ~ *((const nomodify byte*) kbhit::CONIO_CIA1_PORT_B)
+  [40] *((const nomodify byte*) kbhit::CIA1_PORT_A) ← (byte) 0
+  [41] (byte) kbhit::return#0 ← ~ *((const nomodify byte*) kbhit::CIA1_PORT_B)
   to:kbhit::@return
 kbhit::@return: scope:[kbhit]  from kbhit
   [42] return 
@@ -491,7 +491,7 @@ cursor::@return: scope:[cursor]  from cursor
 
 (byte()) bgcolor((byte) bgcolor::color)
 bgcolor: scope:[bgcolor]  from MakeNiceScreen::@5
-  [230] *((const nomodify byte*) CONIO_BGCOLOR) ← (const nomodify byte) COLOR_BLACK
+  [230] *((const nomodify byte*) bgcolor::CONIO_BGCOLOR) ← (const nomodify byte) COLOR_BLACK
   to:bgcolor::@return
 bgcolor::@return: scope:[bgcolor]  from bgcolor
   [231] return 
@@ -499,7 +499,7 @@ bgcolor::@return: scope:[bgcolor]  from bgcolor
 
 (byte()) bordercolor((byte) bordercolor::color)
 bordercolor: scope:[bordercolor]  from MakeNiceScreen::@4
-  [232] *((const nomodify byte*) CONIO_BORDERCOLOR) ← (const nomodify byte) COLOR_BLACK
+  [232] *((const nomodify byte*) bordercolor::CONIO_BORDERCOLOR) ← (const nomodify byte) COLOR_BLACK
   to:bordercolor::@return
 bordercolor::@return: scope:[bordercolor]  from bordercolor
   [233] return 

src/test/ref/examples/conio/nacht-screen.sym

@@ -15,8 +15,6 @@
 (const nomodify byte) CH_VLINE = (byte) $5d
 (const nomodify byte) COLOR_BLACK = (byte) 0
 (const nomodify byte) COLOR_GRAY3 = (byte) $f
-(const nomodify byte*) CONIO_BGCOLOR = (byte*) 53281
-(const nomodify byte*) CONIO_BORDERCOLOR = (byte*) 53280
 (const nomodify byte*) CONIO_SCREEN_COLORS = (byte*) 55296
 (const nomodify byte*) CONIO_SCREEN_TEXT = (byte*) 1024
 (const nomodify byte) CONIO_TEXTCOLOR_DEFAULT = (byte) $e
@@ -64,11 +62,13 @@
 (volatile byte) YSize loadstore zp[1]:18 20.0
 (byte()) bgcolor((byte) bgcolor::color)
 (label) bgcolor::@return
+(const nomodify byte*) bgcolor::CONIO_BGCOLOR = (byte*) 53281
 (byte) bgcolor::color
 (byte) bgcolor::old
 (byte) bgcolor::return
 (byte()) bordercolor((byte) bordercolor::color)
 (label) bordercolor::@return
+(const nomodify byte*) bordercolor::CONIO_BORDERCOLOR = (byte*) 53280
 (byte) bordercolor::color
 (byte) bordercolor::old
 (byte) bordercolor::return
@@ -222,8 +222,8 @@
 (byte) gotoxy::y#7 reg byte a 3.3333333333666668E10
 (byte()) kbhit()
 (label) kbhit::@return
-(const nomodify byte*) kbhit::CONIO_CIA1_PORT_A = (byte*) 56320
-(const nomodify byte*) kbhit::CONIO_CIA1_PORT_B = (byte*) 56321
+(const nomodify byte*) kbhit::CIA1_PORT_A = (byte*) 56320
+(const nomodify byte*) kbhit::CIA1_PORT_B = (byte*) 56321
 (byte) kbhit::return
 (byte) kbhit::return#0 reg byte a 367.33333333333337
 (byte) kbhit::return#2 reg byte a 202.0

src/test/ref/vic20-simple.asm

@@ -0,0 +1,40 @@
+// Trivial VIC 20 program
+  .file [name="vic20-simple.prg", type="prg", segments="Program"]
+.segmentdef Program [segments="Basic, Code, Data"]
+.segmentdef Basic [start=$1001]
+.segmentdef Code [start=$100e]
+.segmentdef Data [startAfter="Code"]
+.segment Basic
+:BasicUpstart(main)
+.segment Code
+
+
+  .const RED = 2
+  // Default address of screen color matrix
+  .label DEFAULT_COLORRAM = $9600
+  // Default address of screen character matrix
+  .label DEFAULT_SCREEN = $1e00
+.segment Code
+main: {
+    ldx #0
+  __b1:
+    // for(char i=0; MESSAGE[i]; i++)
+    lda MESSAGE,x
+    cmp #0
+    bne __b2
+    // }
+    rts
+  __b2:
+    // DEFAULT_SCREEN[i] = MESSAGE[i]
+    lda MESSAGE,x
+    sta DEFAULT_SCREEN,x
+    // DEFAULT_COLORRAM[i] = RED
+    lda #RED
+    sta DEFAULT_COLORRAM,x
+    // for(char i=0; MESSAGE[i]; i++)
+    inx
+    jmp __b1
+}
+.segment Data
+  MESSAGE: .text "hello world!"
+  .byte 0

src/test/ref/vic20-simple.cfg

@@ -0,0 +1,26 @@
+@begin: scope:[]  from
+  [0] phi()
+  to:@1
+@1: scope:[]  from @begin
+  [1] phi()
+  [2] call main 
+  to:@end
+@end: scope:[]  from @1
+  [3] phi()
+
+(void()) main()
+main: scope:[main]  from @1
+  [4] phi()
+  to:main::@1
+main::@1: scope:[main]  from main main::@2
+  [5] (byte) main::i#2 ← phi( main/(byte) 0 main::@2/(byte) main::i#1 )
+  [6] if((byte) 0!=*((const byte*) MESSAGE + (byte) main::i#2)) goto main::@2
+  to:main::@return
+main::@return: scope:[main]  from main::@1
+  [7] return 
+  to:@return
+main::@2: scope:[main]  from main::@1
+  [8] *((const nomodify byte*) DEFAULT_SCREEN + (byte) main::i#2) ← *((const byte*) MESSAGE + (byte) main::i#2)
+  [9] *((const nomodify byte*) DEFAULT_COLORRAM + (byte) main::i#2) ← (const nomodify byte) RED
+  [10] (byte) main::i#1 ← ++ (byte) main::i#2
+  to:main::@1

src/test/ref/vic20-simple.log

@@ -0,0 +1,505 @@
+
+CONTROL FLOW GRAPH SSA
+@begin: scope:[]  from
+  to:@1
+
+(void()) main()
+main: scope:[main]  from @1
+  (byte) main::i#0 ← (byte) 0
+  to:main::@1
+main::@1: scope:[main]  from main main::@2
+  (byte) main::i#2 ← phi( main/(byte) main::i#0 main::@2/(byte) main::i#1 )
+  (bool~) main::$0 ← (number) 0 != *((const byte*) MESSAGE + (byte) main::i#2)
+  if((bool~) main::$0) goto main::@2
+  to:main::@return
+main::@2: scope:[main]  from main::@1
+  (byte) main::i#3 ← phi( main::@1/(byte) main::i#2 )
+  *((const nomodify byte*) DEFAULT_SCREEN + (byte) main::i#3) ← *((const byte*) MESSAGE + (byte) main::i#3)
+  *((const nomodify byte*) DEFAULT_COLORRAM + (byte) main::i#3) ← (const nomodify byte) RED
+  (byte) main::i#1 ← ++ (byte) main::i#3
+  to:main::@1
+main::@return: scope:[main]  from main::@1
+  return 
+  to:@return
+@1: scope:[]  from @begin
+  call main 
+  to:@2
+@2: scope:[]  from @1
+  to:@end
+@end: scope:[]  from @2
+
+SYMBOL TABLE SSA
+(label) @1
+(label) @2
+(label) @begin
+(label) @end
+(const nomodify byte*) DEFAULT_COLORRAM = (byte*)(number) $9600
+(const nomodify byte*) DEFAULT_SCREEN = (byte*)(number) $1e00
+(const byte*) MESSAGE[]  = (byte*) "hello world!"
+(byte) MOS6522_VIA::AUX_CONTROL
+(byte) MOS6522_VIA::INTERRUPT_ENABLE
+(byte) MOS6522_VIA::INTERRUPT_FLAG
+(byte) MOS6522_VIA::PERIPHERAL_CONTROL
+(byte) MOS6522_VIA::PORT_A
+(byte) MOS6522_VIA::PORT_A_DDR
+(byte) MOS6522_VIA::PORT_A_OUTPUT
+(byte) MOS6522_VIA::PORT_B
+(byte) MOS6522_VIA::PORT_B_DDR
+(byte) MOS6522_VIA::SHIFT
+(byte) MOS6522_VIA::TIMER1_HIGH
+(byte) MOS6522_VIA::TIMER1_LATCH_HIGH
+(byte) MOS6522_VIA::TIMER1_LATCH_LOW
+(byte) MOS6522_VIA::TIMER1_LOW
+(byte) MOS6522_VIA::TIMER2_HIGH
+(byte) MOS6522_VIA::TIMER2_LOW
+(byte) MOS6561_VIC::BORDER_BACKGROUND_COLOR
+(byte) MOS6561_VIC::CH1_FREQ
+(byte) MOS6561_VIC::CH2_FREQ
+(byte) MOS6561_VIC::CH3_FREQ
+(byte) MOS6561_VIC::CH4_FREQ
+(byte) MOS6561_VIC::LIGHTPEN_X
+(byte) MOS6561_VIC::LIGHTPEN_Y
+(byte) MOS6561_VIC::MATRIX_COLUMNS
+(byte) MOS6561_VIC::MATRIX_ROWS
+(byte) MOS6561_VIC::MEMORY
+(byte) MOS6561_VIC::ORIGIN_X
+(byte) MOS6561_VIC::ORIGIN_Y
+(byte) MOS6561_VIC::PADDLE_X
+(byte) MOS6561_VIC::PADDLE_Y
+(byte) MOS6561_VIC::RASTER
+(byte) MOS6561_VIC::VOLUME_COLOR
+(const nomodify byte) RED = (byte) 2
+(void()) main()
+(bool~) main::$0
+(label) main::@1
+(label) main::@2
+(label) main::@return
+(byte) main::i
+(byte) main::i#0
+(byte) main::i#1
+(byte) main::i#2
+(byte) main::i#3
+
+Adding number conversion cast (unumber) 0 in (bool~) main::$0 ← (number) 0 != *((const byte*) MESSAGE + (byte) main::i#2)
+Successful SSA optimization PassNAddNumberTypeConversions
+Simplifying constant pointer cast (byte*) 38400
+Simplifying constant pointer cast (byte*) 7680
+Simplifying constant integer cast 0
+Successful SSA optimization PassNCastSimplification
+Finalized unsigned number type (byte) 0
+Successful SSA optimization PassNFinalizeNumberTypeConversions
+Alias main::i#2 = main::i#3 
+Successful SSA optimization Pass2AliasElimination
+Simple Condition (bool~) main::$0 [3] if((byte) 0!=*((const byte*) MESSAGE + (byte) main::i#2)) goto main::@2
+Successful SSA optimization Pass2ConditionalJumpSimplification
+Constant (const byte) main::i#0 = 0
+Successful SSA optimization Pass2ConstantIdentification
+Inlining constant with var siblings (const byte) main::i#0
+Constant inlined main::i#0 = (byte) 0
+Successful SSA optimization Pass2ConstantInlining
+Adding NOP phi() at start of @begin
+Adding NOP phi() at start of @1
+Adding NOP phi() at start of @2
+Adding NOP phi() at start of @end
+Adding NOP phi() at start of main
+CALL GRAPH
+Calls in [] to main:2 
+
+Created 1 initial phi equivalence classes
+Coalesced [12] main::i#4 ← main::i#1
+Coalesced down to 1 phi equivalence classes
+Culled Empty Block (label) @2
+Adding NOP phi() at start of @begin
+Adding NOP phi() at start of @1
+Adding NOP phi() at start of @end
+Adding NOP phi() at start of main
+
+FINAL CONTROL FLOW GRAPH
+@begin: scope:[]  from
+  [0] phi()
+  to:@1
+@1: scope:[]  from @begin
+  [1] phi()
+  [2] call main 
+  to:@end
+@end: scope:[]  from @1
+  [3] phi()
+
+(void()) main()
+main: scope:[main]  from @1
+  [4] phi()
+  to:main::@1
+main::@1: scope:[main]  from main main::@2
+  [5] (byte) main::i#2 ← phi( main/(byte) 0 main::@2/(byte) main::i#1 )
+  [6] if((byte) 0!=*((const byte*) MESSAGE + (byte) main::i#2)) goto main::@2
+  to:main::@return
+main::@return: scope:[main]  from main::@1
+  [7] return 
+  to:@return
+main::@2: scope:[main]  from main::@1
+  [8] *((const nomodify byte*) DEFAULT_SCREEN + (byte) main::i#2) ← *((const byte*) MESSAGE + (byte) main::i#2)
+  [9] *((const nomodify byte*) DEFAULT_COLORRAM + (byte) main::i#2) ← (const nomodify byte) RED
+  [10] (byte) main::i#1 ← ++ (byte) main::i#2
+  to:main::@1
+
+
+VARIABLE REGISTER WEIGHTS
+(byte) MOS6522_VIA::AUX_CONTROL
+(byte) MOS6522_VIA::INTERRUPT_ENABLE
+(byte) MOS6522_VIA::INTERRUPT_FLAG
+(byte) MOS6522_VIA::PERIPHERAL_CONTROL
+(byte) MOS6522_VIA::PORT_A
+(byte) MOS6522_VIA::PORT_A_DDR
+(byte) MOS6522_VIA::PORT_A_OUTPUT
+(byte) MOS6522_VIA::PORT_B
+(byte) MOS6522_VIA::PORT_B_DDR
+(byte) MOS6522_VIA::SHIFT
+(byte) MOS6522_VIA::TIMER1_HIGH
+(byte) MOS6522_VIA::TIMER1_LATCH_HIGH
+(byte) MOS6522_VIA::TIMER1_LATCH_LOW
+(byte) MOS6522_VIA::TIMER1_LOW
+(byte) MOS6522_VIA::TIMER2_HIGH
+(byte) MOS6522_VIA::TIMER2_LOW
+(byte) MOS6561_VIC::BORDER_BACKGROUND_COLOR
+(byte) MOS6561_VIC::CH1_FREQ
+(byte) MOS6561_VIC::CH2_FREQ
+(byte) MOS6561_VIC::CH3_FREQ
+(byte) MOS6561_VIC::CH4_FREQ
+(byte) MOS6561_VIC::LIGHTPEN_X
+(byte) MOS6561_VIC::LIGHTPEN_Y
+(byte) MOS6561_VIC::MATRIX_COLUMNS
+(byte) MOS6561_VIC::MATRIX_ROWS
+(byte) MOS6561_VIC::MEMORY
+(byte) MOS6561_VIC::ORIGIN_X
+(byte) MOS6561_VIC::ORIGIN_Y
+(byte) MOS6561_VIC::PADDLE_X
+(byte) MOS6561_VIC::PADDLE_Y
+(byte) MOS6561_VIC::RASTER
+(byte) MOS6561_VIC::VOLUME_COLOR
+(void()) main()
+(byte) main::i
+(byte) main::i#1 202.0
+(byte) main::i#2 151.5
+
+Initial phi equivalence classes
+[ main::i#2 main::i#1 ]
+Complete equivalence classes
+[ main::i#2 main::i#1 ]
+Allocated zp[1]:2 [ main::i#2 main::i#1 ]
+
+INITIAL ASM
+Target platform is vic20 / MOS6502X
+  // File Comments
+// Trivial VIC 20 program
+  // Upstart
+  .file [name="vic20-simple.prg", type="prg", segments="Program"]
+.segmentdef Program [segments="Basic, Code, Data"]
+.segmentdef Basic [start=$1001]
+.segmentdef Code [start=$100e]
+.segmentdef Data [startAfter="Code"]
+.segment Basic
+:BasicUpstart(main)
+.segment Code
+
+
+  // Global Constants & labels
+  .const RED = 2
+  // Default address of screen color matrix
+  .label DEFAULT_COLORRAM = $9600
+  // Default address of screen character matrix
+  .label DEFAULT_SCREEN = $1e00
+  // @begin
+__bbegin:
+  // [1] phi from @begin to @1 [phi:@begin->@1]
+__b1_from___bbegin:
+  jmp __b1
+  // @1
+__b1:
+  // [2] call main 
+  // [4] phi from @1 to main [phi:@1->main]
+main_from___b1:
+  jsr main
+  // [3] phi from @1 to @end [phi:@1->@end]
+__bend_from___b1:
+  jmp __bend
+  // @end
+__bend:
+.segment Code
+  // main
+main: {
+    .label i = 2
+    // [5] phi from main to main::@1 [phi:main->main::@1]
+  __b1_from_main:
+    // [5] phi (byte) main::i#2 = (byte) 0 [phi:main->main::@1#0] -- vbuz1=vbuc1 
+    lda #0
+    sta.z i
+    jmp __b1
+    // main::@1
+  __b1:
+    // [6] if((byte) 0!=*((const byte*) MESSAGE + (byte) main::i#2)) goto main::@2 -- vbuc1_neq_pbuc2_derefidx_vbuz1_then_la1 
+    lda #0
+    ldy.z i
+    cmp MESSAGE,y
+    bne __b2
+    jmp __breturn
+    // main::@return
+  __breturn:
+    // [7] return 
+    rts
+    // main::@2
+  __b2:
+    // [8] *((const nomodify byte*) DEFAULT_SCREEN + (byte) main::i#2) ← *((const byte*) MESSAGE + (byte) main::i#2) -- pbuc1_derefidx_vbuz1=pbuc2_derefidx_vbuz1 
+    ldy.z i
+    lda MESSAGE,y
+    sta DEFAULT_SCREEN,y
+    // [9] *((const nomodify byte*) DEFAULT_COLORRAM + (byte) main::i#2) ← (const nomodify byte) RED -- pbuc1_derefidx_vbuz1=vbuc2 
+    lda #RED
+    ldy.z i
+    sta DEFAULT_COLORRAM,y
+    // [10] (byte) main::i#1 ← ++ (byte) main::i#2 -- vbuz1=_inc_vbuz1 
+    inc.z i
+    // [5] phi from main::@2 to main::@1 [phi:main::@2->main::@1]
+  __b1_from___b2:
+    // [5] phi (byte) main::i#2 = (byte) main::i#1 [phi:main::@2->main::@1#0] -- register_copy 
+    jmp __b1
+}
+  // File Data
+.segment Data
+  MESSAGE: .text "hello world!"
+  .byte 0
+
+REGISTER UPLIFT POTENTIAL REGISTERS
+Statement [6] if((byte) 0!=*((const byte*) MESSAGE + (byte) main::i#2)) goto main::@2 [ main::i#2 ] ( main:2 [ main::i#2 ] { }  ) always clobbers reg byte a 
+Removing always clobbered register reg byte a as potential for zp[1]:2 [ main::i#2 main::i#1 ]
+Statement [8] *((const nomodify byte*) DEFAULT_SCREEN + (byte) main::i#2) ← *((const byte*) MESSAGE + (byte) main::i#2) [ main::i#2 ] ( main:2 [ main::i#2 ] { }  ) always clobbers reg byte a 
+Statement [9] *((const nomodify byte*) DEFAULT_COLORRAM + (byte) main::i#2) ← (const nomodify byte) RED [ main::i#2 ] ( main:2 [ main::i#2 ] { }  ) always clobbers reg byte a 
+Statement [6] if((byte) 0!=*((const byte*) MESSAGE + (byte) main::i#2)) goto main::@2 [ main::i#2 ] ( main:2 [ main::i#2 ] { }  ) always clobbers reg byte a 
+Statement [8] *((const nomodify byte*) DEFAULT_SCREEN + (byte) main::i#2) ← *((const byte*) MESSAGE + (byte) main::i#2) [ main::i#2 ] ( main:2 [ main::i#2 ] { }  ) always clobbers reg byte a 
+Statement [9] *((const nomodify byte*) DEFAULT_COLORRAM + (byte) main::i#2) ← (const nomodify byte) RED [ main::i#2 ] ( main:2 [ main::i#2 ] { }  ) always clobbers reg byte a 
+Potential registers zp[1]:2 [ main::i#2 main::i#1 ] : zp[1]:2 , reg byte x , reg byte y , 
+
+REGISTER UPLIFT SCOPES
+Uplift Scope [main] 353.5: zp[1]:2 [ main::i#2 main::i#1 ] 
+Uplift Scope [MOS6561_VIC] 
+Uplift Scope [MOS6522_VIA] 
+Uplift Scope [] 
+
+Uplifting [main] best 403 combination reg byte x [ main::i#2 main::i#1 ] 
+Uplifting [MOS6561_VIC] best 403 combination 
+Uplifting [MOS6522_VIA] best 403 combination 
+Uplifting [] best 403 combination 
+
+ASSEMBLER BEFORE OPTIMIZATION
+  // File Comments
+// Trivial VIC 20 program
+  // Upstart
+  .file [name="vic20-simple.prg", type="prg", segments="Program"]
+.segmentdef Program [segments="Basic, Code, Data"]
+.segmentdef Basic [start=$1001]
+.segmentdef Code [start=$100e]
+.segmentdef Data [startAfter="Code"]
+.segment Basic
+:BasicUpstart(main)
+.segment Code
+
+
+  // Global Constants & labels
+  .const RED = 2
+  // Default address of screen color matrix
+  .label DEFAULT_COLORRAM = $9600
+  // Default address of screen character matrix
+  .label DEFAULT_SCREEN = $1e00
+  // @begin
+__bbegin:
+  // [1] phi from @begin to @1 [phi:@begin->@1]
+__b1_from___bbegin:
+  jmp __b1
+  // @1
+__b1:
+  // [2] call main 
+  // [4] phi from @1 to main [phi:@1->main]
+main_from___b1:
+  jsr main
+  // [3] phi from @1 to @end [phi:@1->@end]
+__bend_from___b1:
+  jmp __bend
+  // @end
+__bend:
+.segment Code
+  // main
+main: {
+    // [5] phi from main to main::@1 [phi:main->main::@1]
+  __b1_from_main:
+    // [5] phi (byte) main::i#2 = (byte) 0 [phi:main->main::@1#0] -- vbuxx=vbuc1 
+    ldx #0
+    jmp __b1
+    // main::@1
+  __b1:
+    // [6] if((byte) 0!=*((const byte*) MESSAGE + (byte) main::i#2)) goto main::@2 -- vbuc1_neq_pbuc2_derefidx_vbuxx_then_la1 
+    lda MESSAGE,x
+    cmp #0
+    bne __b2
+    jmp __breturn
+    // main::@return
+  __breturn:
+    // [7] return 
+    rts
+    // main::@2
+  __b2:
+    // [8] *((const nomodify byte*) DEFAULT_SCREEN + (byte) main::i#2) ← *((const byte*) MESSAGE + (byte) main::i#2) -- pbuc1_derefidx_vbuxx=pbuc2_derefidx_vbuxx 
+    lda MESSAGE,x
+    sta DEFAULT_SCREEN,x
+    // [9] *((const nomodify byte*) DEFAULT_COLORRAM + (byte) main::i#2) ← (const nomodify byte) RED -- pbuc1_derefidx_vbuxx=vbuc2 
+    lda #RED
+    sta DEFAULT_COLORRAM,x
+    // [10] (byte) main::i#1 ← ++ (byte) main::i#2 -- vbuxx=_inc_vbuxx 
+    inx
+    // [5] phi from main::@2 to main::@1 [phi:main::@2->main::@1]
+  __b1_from___b2:
+    // [5] phi (byte) main::i#2 = (byte) main::i#1 [phi:main::@2->main::@1#0] -- register_copy 
+    jmp __b1
+}
+  // File Data
+.segment Data
+  MESSAGE: .text "hello world!"
+  .byte 0
+
+ASSEMBLER OPTIMIZATIONS
+Removing instruction jmp __b1
+Removing instruction jmp __bend
+Removing instruction jmp __b1
+Removing instruction jmp __breturn
+Succesful ASM optimization Pass5NextJumpElimination
+Removing instruction __b1_from___bbegin:
+Removing instruction __b1:
+Removing instruction main_from___b1:
+Removing instruction __bend_from___b1:
+Succesful ASM optimization Pass5RedundantLabelElimination
+Removing instruction __bbegin:
+Removing instruction __bend:
+Removing instruction __b1_from_main:
+Removing instruction __breturn:
+Removing instruction __b1_from___b2:
+Succesful ASM optimization Pass5UnusedLabelElimination
+Removing instruction jsr main
+Succesful ASM optimization Pass5SkipBegin
+
+FINAL SYMBOL TABLE
+(label) @1
+(label) @begin
+(label) @end
+(const nomodify byte*) DEFAULT_COLORRAM = (byte*) 38400
+(const nomodify byte*) DEFAULT_SCREEN = (byte*) 7680
+(const byte*) MESSAGE[]  = (byte*) "hello world!"
+(byte) MOS6522_VIA::AUX_CONTROL
+(byte) MOS6522_VIA::INTERRUPT_ENABLE
+(byte) MOS6522_VIA::INTERRUPT_FLAG
+(byte) MOS6522_VIA::PERIPHERAL_CONTROL
+(byte) MOS6522_VIA::PORT_A
+(byte) MOS6522_VIA::PORT_A_DDR
+(byte) MOS6522_VIA::PORT_A_OUTPUT
+(byte) MOS6522_VIA::PORT_B
+(byte) MOS6522_VIA::PORT_B_DDR
+(byte) MOS6522_VIA::SHIFT
+(byte) MOS6522_VIA::TIMER1_HIGH
+(byte) MOS6522_VIA::TIMER1_LATCH_HIGH
+(byte) MOS6522_VIA::TIMER1_LATCH_LOW
+(byte) MOS6522_VIA::TIMER1_LOW
+(byte) MOS6522_VIA::TIMER2_HIGH
+(byte) MOS6522_VIA::TIMER2_LOW
+(byte) MOS6561_VIC::BORDER_BACKGROUND_COLOR
+(byte) MOS6561_VIC::CH1_FREQ
+(byte) MOS6561_VIC::CH2_FREQ
+(byte) MOS6561_VIC::CH3_FREQ
+(byte) MOS6561_VIC::CH4_FREQ
+(byte) MOS6561_VIC::LIGHTPEN_X
+(byte) MOS6561_VIC::LIGHTPEN_Y
+(byte) MOS6561_VIC::MATRIX_COLUMNS
+(byte) MOS6561_VIC::MATRIX_ROWS
+(byte) MOS6561_VIC::MEMORY
+(byte) MOS6561_VIC::ORIGIN_X
+(byte) MOS6561_VIC::ORIGIN_Y
+(byte) MOS6561_VIC::PADDLE_X
+(byte) MOS6561_VIC::PADDLE_Y
+(byte) MOS6561_VIC::RASTER
+(byte) MOS6561_VIC::VOLUME_COLOR
+(const nomodify byte) RED = (byte) 2
+(void()) main()
+(label) main::@1
+(label) main::@2
+(label) main::@return
+(byte) main::i
+(byte) main::i#1 reg byte x 202.0
+(byte) main::i#2 reg byte x 151.5
+
+reg byte x [ main::i#2 main::i#1 ]
+
+
+FINAL ASSEMBLER
+Score: 331
+
+  // File Comments
+// Trivial VIC 20 program
+  // Upstart
+  .file [name="vic20-simple.prg", type="prg", segments="Program"]
+.segmentdef Program [segments="Basic, Code, Data"]
+.segmentdef Basic [start=$1001]
+.segmentdef Code [start=$100e]
+.segmentdef Data [startAfter="Code"]
+.segment Basic
+:BasicUpstart(main)
+.segment Code
+
+
+  // Global Constants & labels
+  .const RED = 2
+  // Default address of screen color matrix
+  .label DEFAULT_COLORRAM = $9600
+  // Default address of screen character matrix
+  .label DEFAULT_SCREEN = $1e00
+  // @begin
+  // [1] phi from @begin to @1 [phi:@begin->@1]
+  // @1
+  // [2] call main 
+  // [4] phi from @1 to main [phi:@1->main]
+  // [3] phi from @1 to @end [phi:@1->@end]
+  // @end
+.segment Code
+  // main
+main: {
+    // [5] phi from main to main::@1 [phi:main->main::@1]
+    // [5] phi (byte) main::i#2 = (byte) 0 [phi:main->main::@1#0] -- vbuxx=vbuc1 
+    ldx #0
+    // main::@1
+  __b1:
+    // for(char i=0; MESSAGE[i]; i++)
+    // [6] if((byte) 0!=*((const byte*) MESSAGE + (byte) main::i#2)) goto main::@2 -- vbuc1_neq_pbuc2_derefidx_vbuxx_then_la1 
+    lda MESSAGE,x
+    cmp #0
+    bne __b2
+    // main::@return
+    // }
+    // [7] return 
+    rts
+    // main::@2
+  __b2:
+    // DEFAULT_SCREEN[i] = MESSAGE[i]
+    // [8] *((const nomodify byte*) DEFAULT_SCREEN + (byte) main::i#2) ← *((const byte*) MESSAGE + (byte) main::i#2) -- pbuc1_derefidx_vbuxx=pbuc2_derefidx_vbuxx 
+    lda MESSAGE,x
+    sta DEFAULT_SCREEN,x
+    // DEFAULT_COLORRAM[i] = RED
+    // [9] *((const nomodify byte*) DEFAULT_COLORRAM + (byte) main::i#2) ← (const nomodify byte) RED -- pbuc1_derefidx_vbuxx=vbuc2 
+    lda #RED
+    sta DEFAULT_COLORRAM,x
+    // for(char i=0; MESSAGE[i]; i++)
+    // [10] (byte) main::i#1 ← ++ (byte) main::i#2 -- vbuxx=_inc_vbuxx 
+    inx
+    // [5] phi from main::@2 to main::@1 [phi:main::@2->main::@1]
+    // [5] phi (byte) main::i#2 = (byte) main::i#1 [phi:main::@2->main::@1#0] -- register_copy 
+    jmp __b1
+}
+  // File Data
+.segment Data
+  MESSAGE: .text "hello world!"
+  .byte 0
+

src/test/ref/vic20-simple.sym

@@ -0,0 +1,48 @@
+(label) @1
+(label) @begin
+(label) @end
+(const nomodify byte*) DEFAULT_COLORRAM = (byte*) 38400
+(const nomodify byte*) DEFAULT_SCREEN = (byte*) 7680
+(const byte*) MESSAGE[]  = (byte*) "hello world!"
+(byte) MOS6522_VIA::AUX_CONTROL
+(byte) MOS6522_VIA::INTERRUPT_ENABLE
+(byte) MOS6522_VIA::INTERRUPT_FLAG
+(byte) MOS6522_VIA::PERIPHERAL_CONTROL
+(byte) MOS6522_VIA::PORT_A
+(byte) MOS6522_VIA::PORT_A_DDR
+(byte) MOS6522_VIA::PORT_A_OUTPUT
+(byte) MOS6522_VIA::PORT_B
+(byte) MOS6522_VIA::PORT_B_DDR
+(byte) MOS6522_VIA::SHIFT
+(byte) MOS6522_VIA::TIMER1_HIGH
+(byte) MOS6522_VIA::TIMER1_LATCH_HIGH
+(byte) MOS6522_VIA::TIMER1_LATCH_LOW
+(byte) MOS6522_VIA::TIMER1_LOW
+(byte) MOS6522_VIA::TIMER2_HIGH
+(byte) MOS6522_VIA::TIMER2_LOW
+(byte) MOS6561_VIC::BORDER_BACKGROUND_COLOR
+(byte) MOS6561_VIC::CH1_FREQ
+(byte) MOS6561_VIC::CH2_FREQ
+(byte) MOS6561_VIC::CH3_FREQ
+(byte) MOS6561_VIC::CH4_FREQ
+(byte) MOS6561_VIC::LIGHTPEN_X
+(byte) MOS6561_VIC::LIGHTPEN_Y
+(byte) MOS6561_VIC::MATRIX_COLUMNS
+(byte) MOS6561_VIC::MATRIX_ROWS
+(byte) MOS6561_VIC::MEMORY
+(byte) MOS6561_VIC::ORIGIN_X
+(byte) MOS6561_VIC::ORIGIN_Y
+(byte) MOS6561_VIC::PADDLE_X
+(byte) MOS6561_VIC::PADDLE_Y
+(byte) MOS6561_VIC::RASTER
+(byte) MOS6561_VIC::VOLUME_COLOR
+(const nomodify byte) RED = (byte) 2
+(void()) main()
+(label) main::@1
+(label) main::@2
+(label) main::@return
+(byte) main::i
+(byte) main::i#1 reg byte x 202.0
+(byte) main::i#2 reg byte x 151.5
+
+reg byte x [ main::i#2 main::i#1 ]