implemented 'GO' BASIC command, started work on native MEGA65 mode

src/aliases/,aliases_ram_lowmem_m65.s

@@ -0,0 +1,31 @@
+// #LAYOUT# M65 * #TAKE
+// #LAYOUT# *   * #IGNORE
+
+//
+// Names of ZP and low memory locations for the native Mega65 mode
+//
+
+
+	//
+	// Page 0 - reused LDTB1
+	//
+
+	                            // $D9      -- UNUSED --
+	.label M65_LPNT_BAS1 = $DA  // $DA-$DD  4-byte pointer for temporary usage within BASIC
+	.label M65_LPNT_BAS2 = $DE  // $DE-$E1  4-byte pointer for temporary usage within BASIC
+	.label M65_LPNT_SCR  = $E2  // $E2-$E5  4-byte pointer for temporary usage within BASIC and screen editor
+	                            // E6      reserved for BASIC error handling routines, also in native mode
+	.label M65_MAGICSTR  = $E7  // $E7-$E9  if equals 'M65' it means we are in native mode
+	.label M65_LPNT_IRQ  = $EA  // $EA-$ED  4-byte pointer for temporary usage within interrupts
+	.label M65_LPNT_KERN = $EE  // $EE-$F1  4-byte pointer for temporary usage by KERNAL
+	                            // $F2      -- UNUSED --
+
+	//
+	// Pages 4-7 - reused screen memory
+	//
+
+	                               // $400-$57F -- UNUSED -- reserved for BASIC
+	                               // $580-$5FF -- UNUSED -- reserved for KERNAL
+
+	.label M65_RS232_INBUF  = $600 // $600-$6FF  -- reserved for RS-232 input buffer --
+	.label M65_RS232_OUTBUF = $700 // $700-$7FF  -- reserved for RS-232 output buffer --

src/basic/,imports.s

@@ -51,3 +51,11 @@
 #endif
 
 .label filename_any        = KERNAL().filename_any
+
+#if ROM_LAYOUT_M65
+.label M65_JMODE64         = KERNAL().M65_JMODE64
+.label M65_JMODE65         = KERNAL().M65_JMODE65
+.label M65_JISMODE65       = KERNAL().M65_JISMODE65
+.label M65_JSLOW           = KERNAL().M65_JSLOW
+.label M65_JFAST           = KERNAL().M65_JFAST
+#endif

src/basic/basic_commands/cmd__unimplemented.s

@@ -51,8 +51,6 @@ cmd_tab:
 	nop
 cmd_spc:
 	nop
-cmd_go:
-	nop
 
 	// Unimplemented tokens
 

src/basic/basic_commands/cmd_go_goto_run.s

@@ -3,6 +3,61 @@
 // #LAYOUT# *   *       #IGNORE
 
 
+cmd_go:
+
+	jsr fetch_character_skip_spaces
+
+	cmp #$A4                           // 'TO' keyword
+	beq cmd_goto
+
+#if !ROM_LAYOUT_M65
+
+	// FALLTROUGH
+
+cmd_go_syntax_error:
+
+	jmp do_SYNTAX_error
+
+#else 
+
+	dew TXTPTR                         // unconsume character
+
+	// Fetch mode
+
+	jsr fetch_uint8
+
+	cmp #64
+	bne !+
+
+	// If in native mode - switch to C64 compatibilty
+
+	jsr M65_JISMODE65
+	bne cmd_go_rts
+
+	jsr helper_ask_if_sure
+	bcs cmd_go_rts
+	jmp M65_JMODE64
+!:
+	cmp #65
+	bne !+
+
+	// If in C64 compatibility mode - switch to native mode
+
+	jsr M65_JISMODE65
+	beq cmd_go_rts
+
+	jsr helper_ask_if_sure
+	bcs cmd_go_rts
+	jmp M65_JMODE65
+!:
+	jmp do_ILLEGAL_QUANTITY_error
+
+cmd_go_rts:
+
+	rts
+
+#endif
+
 cmd_run:
 
 	// RUN clears all variables
@@ -27,7 +82,11 @@ cmd_goto:
 	// GOTO requires line number
 
 	jsr fetch_line_number
+#if !ROM_LAYOUT_M65
+	bcs cmd_go_syntax_error
+#else
 	bcs_16 do_SYNTAX_error
+#endif
 
 	// Check for direct mode
 

src/basic/basic_commands_01/cmd__jumptable_01.s

@@ -9,8 +9,18 @@
 
 .const command_01_list = List().add(
 
+#if CONFIG_MB_MEGA_65
+
+	M65_JSLOW,
+	M65_JFAST,
+
+#else
+
 	cmd_slow,
 	cmd_fast,
+
+#endif
+
 	cmd_old,
 
 	// NOTE! These commands are temporarily placed here, they should be a part of list 02!

src/basic/basic_commands_01/cmd_fast_slow.s

@@ -5,23 +5,7 @@
 
 #if CONFIG_MB_MEGA_65
 
-	// Command implementation for Mega65
-
-	// XXX - I think there are some bit-set instructions in 65CE02...
-
-cmd_slow:
-
-	lda #$40
-	skip_2_bytes_trash_nvz
-
-	// FALLTROUGH
-
-cmd_fast:
-
-	lda #$41
-	sta CPU_D6510
-	rts
-
+	// For Mega65 Kernal routines are called directly
 
 #elif CONFIG_MB_ULTIMATE_64
 

src/kernal/board_m65/mega65_jumptable.s

@@ -0,0 +1,129 @@
+// #LAYOUT# M65 KERNAL_0 #TAKE
+// #LAYOUT# *   *        #IGNORE
+
+//
+// Not this is not an official Kernal API extension (yet)! It is subject to change!
+//
+
+
+M65_JMODE64:
+
+	// Disable interrupts, they might interfere
+
+	sei
+
+	// XXX provide full implementation
+
+	// Set the magic string to mark legacy mode
+
+	lda #$00
+	sta M65_MAGICSTR+0
+	sta M65_MAGICSTR+1
+	sta M65_MAGICSTR+2
+
+	// Reenable interrupts
+
+	cli
+
+	// Switch CPU speed back to slow and quit
+
+	jmp M65_JSLOW
+
+
+
+M65_JMODE65:
+
+	// Disable interrupts, they might interfere
+
+	sei
+
+	// Swithc CPU speed to fast
+
+	jsr M65_JFAST
+
+	// Set the magic string to mark native mode
+
+	lda #$4D // 'M'
+	sta M65_MAGICSTR+0
+	lda #$36 // '6'
+	sta M65_MAGICSTR+1
+	lda #$35 // '5'
+	sta M65_MAGICSTR+2
+
+	// XXX provide full implementation
+
+	// Switch VIC to VIC-IV mode
+
+	lda #$47
+	sta VIC_KEY
+	lda #$53
+	sta VIC_KEY
+
+	// XXX provide proper implementation
+
+	// Set screen mode to 80 columns
+
+	lda $D031
+	ora #$80
+	sta $D031
+
+	// Set screen RAM base to $15000
+
+	lda #$00
+	sta $D060
+	sta LDTB1+0
+	sta $D063
+	sta LDTB1+3
+	lda #$50
+	sta $D061
+	sta LDTB1+1
+	lda #$01
+	sta $D062
+	sta LDTB1+2
+
+	// Set something in screen memory
+
+	lda #$01
+
+	// STA [],Z
+	nop
+	.byte $92
+	.byte LDTB1
+
+!:
+	nop
+	jmp !-
+
+
+
+M65_JISMODE65: // checks if mode is native M65 one, BEQ = jump if native mode
+
+	pha
+
+	lda M65_MAGICSTR+0
+	cmp #$4D // 'M'
+	bne !+
+	lda M65_MAGICSTR+1
+	cmp #$36 // '6'
+	bne !+
+	lda M65_MAGICSTR+2
+	cmp #$35 // '5'
+!:
+	pla
+	rts
+
+
+
+
+M65_JSLOW: // set CPU speed to 1 MHz
+
+	lda #$40
+	skip_2_bytes_trash_nvz
+
+	// FALLTROUGH
+
+M65_JFAST: // set CPU speed to 40 MHz
+
+	lda #$41
+	sta CPU_D6510
+	rts