feat: optimizations

devices/keyboard.asm

@@ -1,7 +1,6 @@
 #importonce
 #import "../core/module.asm"
 #import "../libs/memory.asm"
-#import "../core/module.asm"
 
 
 .filenamespace Keyboard

devices/video.asm

@@ -145,6 +145,8 @@ init: {
                 sta     MemMap.VIDEO.CursorRow
                 lda     #%00000000
                 sta     MemMap.VIDEO.StatusBitsA
+                lda #COLUMN_NUM
+                sta MemMap.MATH.factor2
                 rts
 }
 
@@ -189,37 +191,34 @@ sendChar: {
     sei
     phx
     cmp     #CR
-                bne     !+
+    bne     notCR
     jsr     screenNewLine
     iny
     jmp     exit
-        !:
+
+notCR:
     cmp     #BS
-                bne     !+
+    bne     notBS
     ldx     MemMap.VIDEO.CursorCol
-                cmp     #0
     beq     exit
     dec     MemMap.VIDEO.CursorCol
-        !:
+    jmp     storeBaseVideoAddress
+
+notBS:
     // Store Base Video Address 16 bit
+storeBaseVideoAddress:
     ldx     #<VIDEO_ADDR         // Low byte
     stx     MemMap.VIDEO.TempVideoPointer
     ldx     #>VIDEO_ADDR         // High byte
     stx     MemMap.VIDEO.TempVideoPointer+1
 
-                // Temp Save Y
-                phy
-
     // CursorRow * 40
     ldy     MemMap.VIDEO.CursorRow
     sty     MemMap.MATH.factor1
-                ldy     #COLUMN_NUM
-                sty     MemMap.MATH.factor2
     jsr     Math.multiply
 
     // Add mul result to TempVideoPointer
     pha
-
     clc
     lda     MemMap.MATH.result
     adc     MemMap.VIDEO.TempVideoPointer+1
@@ -233,36 +232,33 @@ sendChar: {
     bcc     noEndOfLine
     jsr     screenNewLine                   // Yes? Add new line first
 
-                bitTest(%00000001, MemMap.VIDEO.StatusBitsA)
+    lda     MemMap.VIDEO.StatusBitsA
-                bne     noScrollTriggered
+    and     #%00000001
+    beq     noScrollTriggered
 
     // Compensate Scroll
     sec
     lda     MemMap.VIDEO.TempVideoPointer
     sbc     #40
     sta     MemMap.VIDEO.TempVideoPointer
-                bcs     !+
+    bcs     noScrollTriggered
     dec     MemMap.VIDEO.TempVideoPointer+1
-        !:
 
-        noScrollTriggered:
+noScrollTriggered:
-        noEndOfLine:
+noEndOfLine:
     pla
-                // This is a backspace
     cmp     #BS
-                bne     !+
+    bne     notBackspace
     lda     #' '
     sta     (MemMap.VIDEO.TempVideoPointer), y
-                ply
     jmp     exit
-        !:
+
-                // insert into screen
+notBackspace:
     sta     (MemMap.VIDEO.TempVideoPointer), y
-                ply
     iny
     inc     MemMap.VIDEO.CursorCol
 
-        exit:
+exit:
     plx
     cli
     rts

hardware/vic.asm

@@ -1,39 +1,45 @@
 #importonce
 .filenamespace Vic
+
+// VIC registers and constants
+// For more information, refer to:
 // https://www.c64-wiki.com/wiki/VIC
 // https://www.c64-wiki.com/wiki/Page_208-211
 
-// ========================================================
+// Base address for VIC registers
-// ////// CONSTANTS ///////////////////////////////////////
-// ========================================================
-
 .label VICREG = $D000
 
-.label          CR2     = $D016      // Control register 2
+// Control register 2
-.label          INTE    = $D01A      // Interrupt enabled
+.label CR2 = $D016
-.label          RCNT    = $D012      // Raster counter
 
+// Interrupt enabled register
+.label INTE = $D01A
+
+// Raster counter register
+.label RCNT = $D012
 
 
 * = * "VIC Functions"
 
+// Initialize the VIC registers with values from the tvic array
 init: {
-                ldx     #47
+    ldx #47            // Set index to 47 (the number of bytes in tvic)
-    px4:
+load_loop:            // Start of loop to load tvic values into VIC registers
-                lda tvic-1, x
+    lda tvic-1, x     // Load the byte from tvic at position x into the accumulator
-                sta VICREG-1, x
+    sta VICREG-1, x   // Store the byte in the accumulator into the VIC register at position x
-                dex
+    dex               // Decrement the index
-                bne px4
+    bne load_loop     // If the index is not zero, repeat the loop
-                rts
+    rts               // Return from subroutine
 }
 
 * = * "VIC Init Data"
 
+// Initial values for the VIC registers
 tvic:
+    // The following bytes are loaded into the VIC registers in the init subroutine
     .byte $00, $00, $00, $00, $00, $00, $00, $00
     .byte $00, $00, $00, $00, $00, $00, $00, $00
     .byte $00, $9B, $37, $00, $00, $00, $08, $00
     .byte $14, $0F, $00, $00 ,$00, $00, $00, $00
     .byte $0E, $06, $01, $02, $03, $04, $00, $01
     .byte $02, $03, $04, $05, $06, $07, $4C
-

libs/memory.asm

@@ -127,8 +127,9 @@ clone: {
     sei
     ldy     #0
     ldx     MemMap.MEMORY.size
-                beq     md2
+    beq     checkHighByte
-        md1:    lda     (MemMap.MEMORY.from),y // move a page at a time
+md1:    
+    lda     (MemMap.MEMORY.from),y // move a page at a time
     sta     (MemMap.MEMORY.dest),y
     iny
     bne     md1
@@ -136,15 +137,15 @@ clone: {
     inc     MemMap.MEMORY.dest+1
     dex
     bne     md1
-        md2:    ldx     MemMap.MEMORY.size+1
+checkHighByte:
-                beq     md4
+    ldx     MemMap.MEMORY.size+1
-        md3:    lda     (MemMap.MEMORY.from),y // move the remaining bytes
+md3:    
+    lda     (MemMap.MEMORY.from),y // move the remaining bytes
     sta     (MemMap.MEMORY.dest),y
     iny
     dex
     bne     md3
     cli
-        md4:
     plr
     rts
 }
@@ -165,23 +166,16 @@ fill: {
     sei
     ldy     #0
     ldx     MemMap.MEMORY.size
-                beq     md2
+    cpx     MemMap.MEMORY.size+1
-        md1:
+    stx     MemMap.MEMORY.size+1
+fillLoop:
     sta     (MemMap.MEMORY.dest),y
     iny
-                bne     md1
+    bne     fillLoop
     inc     MemMap.MEMORY.dest+1
     dex
-                bne     md1
+    bne     fillLoop
-        md2:    ldx     MemMap.MEMORY.size+1
-                beq     md4
-        md3:
-                sta     (MemMap.MEMORY.dest),y
-                iny
-                dex
-                bne     md3
     cli
-        md4:
     plr
     rts
 }

libs/print.asm

@@ -87,6 +87,10 @@ printLine: {
                 rts
 }
 
+
+// Hexadecimal lookup table
+hexTable: .text "0123456789ABCDEF"
+
 // --------------------------------------------------------
 // byteToHex -
 // Convert a byte to an HEX value
@@ -99,22 +103,21 @@ printLine: {
 //      X       = lns ascii char result
 // --------------------------------------------------------
 byteToHex: {
-                pha
+    tay                    // Save the original byte in Y
-                jsr !+
+    and #$0F               // Mask the lower 4 bits (nibble)
-                tax
+    tax                    // Transfer the lower nibble to X register
-                pla
+    lda hexTable, x        // Load the ASCII value of the least significant hex digit
+    tya                    // Restore the original byte from Y
+    lsr                    // Shift the upper 4 bits (nibble) to the right
     lsr
     lsr
     lsr
-                lsr
+    tax                    // Transfer the upper nibble to X register
-
+    pha                    // Push the ASCII value of the least significant hex digit to stack
-        !:	and #$0f
+    lda hexTable, x        // Load the ASCII value of the most significant hex digit
-                cmp #$0a
+    tax                    // Transfer the ASCII value of the most significant hex digit to X
-                bcc !+
+    pla                    // Pop the ASCII value of the least significant hex digit from stack to A
-                adc #6
+    rts                    // Return from the function                  // Return from the function
-
-        !:	adc #'0'
-                rts
 }
 
 // --------------------------------------------------------

libs/timers.asm

@@ -48,21 +48,28 @@ delayOne: {
     pha
     lda     #$00
     sta     MemMap.TIMERS.counter
-    loop1:      lda     #$fb    // wait for vertical retrace
+
-    loop2:      cmp     $d012   // until it reaches 251th raster line ($fb)
+loop1:
-                bne     loop2       // which is out of the inner screen area
+    lda     #$fb // wait for vertical retrace
+
+loop2:
+    cmp     $d012 // until it reaches 251th raster line ($fb)
+    beq     waitForNextLine
+    jmp     loop2 // loop back if not yet at the 251th raster line
+
+waitForNextLine:
+    lda     $d012 // make sure we reached
+
+loop3:
+    cmp     $d012 // the next raster line so next time we
+    beq     loop1 // jump back to the main loop if still on the same raster line
+
     inc     MemMap.TIMERS.counter // increase frame counter
     lda     MemMap.TIMERS.counter // check if counter
     cmp     #$32 // reached 50
-                bne     out         // if not, pass the color changing routine
+    bne     loop1 // if not, jump back to the main loop
-                jmp     exit
 
-    out:
+exit:
-                lda     $d012   // make sure we reached
-    loop3:      cmp     $d012   // the next raster line so next time we
-                beq     loop3
-                jmp loop1 // jump to main loop
-    exit:
     pla
     rts
 }

main.asm

@@ -1,6 +1,6 @@
 .cpu _6502
 
-BasicUpstart2(Boot.warmStart)
+//BasicUpstart2(Boot.warmStart)
 #import "./hardware/mem_map.asm"
 
 * = $8000 "Main"

makefile

@@ -1,22 +1,28 @@
 BUILD_PATH = ./bin
-KICKASS_BIN = /opt/develop/stid/c64/KickAssembler/KickAss.jar
+KICKASS_BIN = /Applications/KickAssembler/KickAss.jar
+PRG_FILE = ${BUILD_PATH}/main.prg
+CRT_FILE = ${BUILD_PATH}/woz.crt
+
+.PHONY: all build eprom clean run
 
 all: build
 
-build:
+build: ${PRG_FILE} ${CRT_FILE}
-	java -jar ${KICKASS_BIN} -odir ${BUILD_PATH} -log ${BUILD_PATH}/buildlog.txt -showmem ./main.asm
-	cartconv -t normal -name "woz" -i ${BUILD_PATH}/main.prg -o ${BUILD_PATH}/woz.crt
 
-eprom:
+eprom: ${PRG_FILE} ${CRT_FILE}
-	java -jar ${KICKASS_BIN} -odir ${BUILD_PATH} -log ${BUILD_PATH}/buildlog.txt -showmem ./main.asm
+	cartconv -i ${CRT_FILE} -o ${BUILD_PATH}/woz.bin
-	cartconv -t normal -name "woz" -i ${BUILD_PATH}/main.prg -o ${BUILD_PATH}/woz.crt
-	cartconv -i ${BUILD_PATH}/woz.crt -o ${BUILD_PATH}/woz.bin
 
 clean:
-	rm -Rf ./bin
+	rm -Rf $(BUILD_PATH)
 
-run:
+run: build
+	x64sc $(CRT_FILE)
+
+${BUILD_PATH}:
+	mkdir -p $(BUILD_PATH)
+
+${PRG_FILE}: ${BUILD_PATH}
 	java -jar ${KICKASS_BIN} -odir ${BUILD_PATH} -log ${BUILD_PATH}/buildlog.txt -showmem ./main.asm
-	cartconv -t normal -name "woz" -i ${BUILD_PATH}/main.prg -o ${BUILD_PATH}/woz.crt
-	x64sc ${BUILD_PATH}/woz.crt
 
+${CRT_FILE}: ${PRG_FILE}
+	cartconv -t normal -n "woz" -i $(PRG_FILE) -o $(CRT_FILE)