Refactor disassembled instructions to be fixed arr

Updated code to make disassembled instructions a fixed array since we
know the cap at runtime, Also added toggle switch to follow the current
instruction

src/simulator/gui.odin

@@ -3,26 +3,26 @@ package simulator
 import emu "../machine"
 import rl "vendor:raylib"
 
-// @ Window
+// Window
 WINDOW_WIDTH  :: 1920
 WINDOW_HEIGHT :: 1080
 
-// @ Layout proportions
+// Layout proportions
 // Sidebar takes 20% of screen width on each side; display takes the rest.
 // The center column splits vertically: 40% display, 60% debug panel.
 SIDEBAR_PERCENT		:: f32(0.20)
 DISPLAY_V_RATIO		:: f32(0.40)
-// @ Fixed heights
+// Fixed heights
 CONTROL_BAR_H		:: f32(50)
 STATUS_BAR_H		:: f32(30)
-// @ Layout constants
+// Layout constants
 PADDING_X			:: f32(10)
 PADDING_Y			:: f32(8)
 PANEL_HEADER		:: f32(24)
-// @ Buttons
+// Buttons
 BUTTON_HEIGHT		:: 30
 BUTTON_WIDTH		:: 120
-// @ Fonts
+// Fonts
 BIG_FONT_SIZE		:: 20
 KEYPAD_FONT_SIZE	:: 18
 
@@ -50,7 +50,7 @@ run_gui :: proc(sim: ^Simulator) {
     sim.font = font
 
     rl.GuiLoadStyleDefault()
-    rl.GuiLoadStyle("./assets/raygui_styles/style_dark.rgs")
+    rl.GuiLoadStyle("./assets/raygui_styles/genesis.rgs")
 
     rl.GuiSetFont(font)
     rl.GuiSetStyle(.DEFAULT, i32(rl.GuiDefaultProperty.TEXT_SIZE), 18)
@@ -67,23 +67,19 @@ run_gui :: proc(sim: ^Simulator) {
 		layout := calc_layout(screen_width, screen_height)
 
 		rl.BeginDrawing()
-		rl.ClearBackground(rl.BLACK)
+		rl.ClearBackground(rl.Color{0x18, 0x18, 0x18, 0xFF})
 
 		if (!sim.paused) {
 			// Cycle the machine to update memory etc
 			emu.run_machine(sim.machine, 12)
+			tick_timers(sim, beep)
+		}
 
-			// Handle delay timer
-			if sim.machine.delay_timer > 0 do sim.machine.delay_timer -= 1
-
-			// Current sound file is around 1s so stop
-			// immediately when timer is 0
-			if sim.machine.sound_timer > 0 {
-				sim.machine.sound_timer -= 1
-				if !rl.IsSoundPlaying(beep) do rl.PlaySound(beep)
-			} else {
-				rl.StopSound(beep)
-			}
+		if(sim.paused && sim.step) {
+			// Cycle the machine to update memory etc
+			emu.run_machine(sim.machine, 1)
+			tick_timers(sim, beep)
+			sim.step = false
 		}
 
 		// Top
@@ -115,12 +111,18 @@ run_gui :: proc(sim: ^Simulator) {
 	rl.UnloadSound(beep)
 	rl.CloseAudioDevice()
 	rl.CloseWindow()
-
-	// Free any allocated memory for the simulator
-	delete(sim.disasm)
 }
 
-// @TODO: If this grows lets move it into its own file
+tick_timers :: proc(sim: ^Simulator, beep: rl.Sound) {
+    if sim.machine.delay_timer > 0 do sim.machine.delay_timer -= 1
+    if sim.machine.sound_timer > 0 {
+        sim.machine.sound_timer -= 1
+        if !rl.IsSoundPlaying(beep) do rl.PlaySound(beep)
+    } else {
+        rl.StopSound(beep)
+    }
+}
+
 calc_layout :: proc(screen_width: f32, screen_height: f32) -> Layout {
 	// Control bar is a fixed height frozen at top of gui, all items start below it.
 	y_pos			   := CONTROL_BAR_H

src/simulator/gui_control_bar.odin

@@ -1,6 +1,8 @@
 package simulator
 
 import "core:log"
+
+import emu "../machine"
 import rl "vendor:raylib"
 
 gui_control_bar :: proc(rect: rl.Rectangle, sim: ^Simulator) {
@@ -15,7 +17,6 @@ gui_control_bar :: proc(rect: rl.Rectangle, sim: ^Simulator) {
 	if btn(&cursor, rect, BUTTON_HEIGHT, BUTTON_WIDTH, PADDING_X, "RUN") {
 		if sim.rom_loaded {
 			sim.paused = false
-			sim.running = true
 		} else {
 			log.info("no rom selected, can't run")
 		}
@@ -23,12 +24,26 @@ gui_control_bar :: proc(rect: rl.Rectangle, sim: ^Simulator) {
 
 	if btn(&cursor, rect, BUTTON_HEIGHT, BUTTON_WIDTH, PADDING_X, "PAUSE") {
 		sim.paused = true
-		sim.running = false
+	}
+
+	if btn(&cursor, rect, BUTTON_HEIGHT, BUTTON_WIDTH, PADDING_X, "STEP") {
+		if !sim.step do sim.step = true
 	}
 
 	if btn(&cursor, rect, BUTTON_HEIGHT, BUTTON_WIDTH, PADDING_X, "RESET") {
-
+		sim.paused = true
+		sim.disasm_count = 0
+		emu.reset_machine(sim.machine)
 	}
+
+	// @TODO: Get this working
+	slider_rect := rl.Rectangle{
+		x = rect.width - 100 - 50,
+		y = rect.y + 15,
+		width = 100,
+		height = 15
+	}
+	rl.GuiSlider(slider_rect, "Speed  ", nil, &sim.speed_value, 0, 100)
 }
 
 btn :: proc(cursor: ^f32, rect: rl.Rectangle, h, w, gap: f32, label: cstring) -> bool {

src/simulator/gui_file_loader.odin

@@ -7,12 +7,6 @@ import rl "vendor:raylib"
 import emu "../machine"
 import tfd "../../external/tinyfiledialogs"
 
-Instruction :: struct {
-	address: u16,
-	raw:	 u16,
-	str:     string
-}
-
 gui_file_loader :: proc(rect: rl.Rectangle, sim: ^Simulator) {
 	rl.DrawRectangleLinesEx(rect, 1, rl.GRAY)
 
@@ -39,7 +33,7 @@ gui_file_loader :: proc(rect: rl.Rectangle, sim: ^Simulator) {
 		rom_path := string(ret)
 		if rom_path == "" do return
 
-		// reset machine state
+		// Reset machine state
 		emu.reset_machine(sim.machine)
 
 		// load new rom
@@ -48,12 +42,8 @@ gui_file_loader :: proc(rect: rl.Rectangle, sim: ^Simulator) {
 			// @TODO: update status bar here
 			panic("failed to load rom!")
 		}
-
 		sim.rom_loaded = true
-
-		// Free old instructions on sim
-		delete(sim.disasm)
-		sim.disasm = disassemble_rom(sim.machine.memory[:], 0x200, 0x200 + u16(rom_size))
+		sim.disasm_count = disassemble_rom_n(sim.machine.memory[:], 0x200, 0x200 + u16(rom_size), sim.disasm[:])
 	}
 
 	// drop-zone occupies the panel's content area, minus space for the button
@@ -108,12 +98,14 @@ gui_file_loader :: proc(rect: rl.Rectangle, sim: ^Simulator) {
 	rl.GuiButton(bottom_btn_rect, "Open ROM Folder")
 }
 
-disassemble_rom :: proc(memory: []u8, start: u16, end_addr: u16) -> []Instruction {
-	entries := make([dynamic]Instruction)
+disassemble_rom_n :: proc(memory: []u8, start_addr: u16, end_addr: u16, out: []Instruction) -> int {
+	count := 0
+	i := start_addr
 
-	i := start
 	for i < end_addr {
 		if int(i) + 1 >= len(memory) do break
+        if count >= len(out) do break
+
 		addr	  := i
 		high_byte := memory[i]
 		low_byte  := memory[i + 1]
@@ -130,63 +122,68 @@ disassemble_rom :: proc(memory: []u8, start: u16, end_addr: u16) -> []Instructio
 		kk           := u8(opcode & 0x00FF)		// An 8-bit value, the lowest 8 bits of the instruction
 		nnn          := (opcode & 0x0FFF)		// A 12-bit value, the lowest 12 bits of the instruction
 
-		str: string
+
+		instruction := &out[count]
+		instruction.address = addr
+		instruction.raw = opcode
+
 		switch first_nibble {
             case 0x0:
                 switch opcode {
-                    case 0x00E0: str = "CLS"
-                    case 0x00EE: str = "RET"
-                    case:        str = fmt.tprintf("DATA 0x%04X", opcode)
+                    //case 0x00E0: str = "CLS"
+					case 0x00E0: fmt.bprintf(instruction.str[:], "CLS")
+                    case 0x00EE: fmt.bprintf(instruction.str[:], "RET")
+                    case:        fmt.bprintf(instruction.str[:], "DATA 0x%04X", opcode)
                 }
-			case 0x1: str = fmt.tprintf("JP 0x%03X", nnn)
-			case 0x2: str = fmt.tprintf("CALL 0x%03X", nnn)
-			case 0x3: str = fmt.tprintf("SE V%X, 0x%02X", vx, kk)
-			case 0x4: str = fmt.tprintf("SNE V%X, 0x%02X", vx, kk)
-			case 0x5: str = fmt.tprintf("SE V%X, V%X", vx, vy)
-			case 0x6: str = fmt.tprintf("LD V%X, 0x%02X", vx, kk)
-			case 0x7: str = fmt.tprintf("ADD V%X, 0x%02X", vx, kk)
+			case 0x1: fmt.bprintf(instruction.str[:], "JP 0x%03X", nnn)
+			case 0x2: fmt.bprintf(instruction.str[:], "CALL 0x%03X", nnn)
+			case 0x3: fmt.bprintf(instruction.str[:], "SE V%X, 0x%02X", vx, kk)
+			case 0x4: fmt.bprintf(instruction.str[:], "SNE V%X, 0x%02X", vx, kk)
+			case 0x5: fmt.bprintf(instruction.str[:], "SE V%X, V%X", vx, vy)
+			case 0x6: fmt.bprintf(instruction.str[:], "LD V%X, 0x%02X", vx, kk)
+			case 0x7: fmt.bprintf(instruction.str[:], "ADD V%X, 0x%02X", vx, kk)
 			case 0x8:
 				switch last_nibble {
-					case 0x0: str = fmt.tprintf("LD V%X, V%X", vx, vy)
-					case 0x1: str = fmt.tprintf("OR V%X, V%X", vx, vy)
-					case 0x2: str = fmt.tprintf("AND V%X, V%X", vx, vy)
-					case 0x3: str = fmt.tprintf("XOR V%X, V%X", vx, vy)
-					case 0x4: str = fmt.tprintf("ADD V%X, V%X", vx, vy)
-					case 0x5: str = fmt.tprintf("SUB V%X, V%X", vx, vy)
-					case 0x6: str = fmt.tprintf("SHR V%X", vx)
-					case 0x7: str = fmt.tprintf("SUBN V%X, V%X", vx, vy)
-					case 0xE: str = fmt.tprintf("SHL V%X", vx)
-					case:     str = fmt.tprintf("DATA 0x%04X", opcode)
+					case 0x0: fmt.bprintf(instruction.str[:], "LD V%X, V%X", vx, vy)
+					case 0x1: fmt.bprintf(instruction.str[:], "OR V%X, V%X", vx, vy)
+					case 0x2: fmt.bprintf(instruction.str[:], "AND V%X, V%X", vx, vy)
+					case 0x3: fmt.bprintf(instruction.str[:], "XOR V%X, V%X", vx, vy)
+					case 0x4: fmt.bprintf(instruction.str[:], "ADD V%X, V%X", vx, vy)
+					case 0x5: fmt.bprintf(instruction.str[:], "SUB V%X, V%X", vx, vy)
+					case 0x6: fmt.bprintf(instruction.str[:], "SHR V%X", vx)
+					case 0x7: fmt.bprintf(instruction.str[:], "SUBN V%X, V%X", vx, vy)
+					case 0xE: fmt.bprintf(instruction.str[:], "SHL V%X", vx)
+					case:     fmt.bprintf(instruction.str[:], "DATA 0x%04X", opcode)
 				}
-			case 0x9: str = fmt.tprintf("SNE V%X, V%X", vx, vy)
-			case 0xA: str = fmt.tprintf("LD I, 0x%03X", nnn)
-			case 0xB: str = fmt.tprintf("JP V0, 0x%03X", nnn)
-			case 0xC: str = fmt.tprintf("RND V%X, 0x%02X", vx, kk)
-			case 0xD: str = fmt.tprintf("DRW V%X, V%X, %X", vx, vy, last_nibble)
+			case 0x9: fmt.bprintf(instruction.str[:], "SNE V%X, V%X", vx, vy)
+			case 0xA: fmt.bprintf(instruction.str[:], "LD I, 0x%03X", nnn)
+			case 0xB: fmt.bprintf(instruction.str[:], "JP V0, 0x%03X", nnn)
+			case 0xC: fmt.bprintf(instruction.str[:], "RND V%X, 0x%02X", vx, kk)
+			case 0xD: fmt.bprintf(instruction.str[:], "DRW V%X, V%X, %X", vx, vy, last_nibble)
 			case 0xE:
 				switch kk {
-					case 0x9E: str = fmt.tprintf("SKP V%X", vx)
-					case 0xA1: str = fmt.tprintf("SKNP V%X", vx)
-					case:      str = fmt.tprintf("DATA 0x%04X", opcode)
+					case 0x9E: fmt.bprintf(instruction.str[:], "SKP V%X", vx)
+					case 0xA1: fmt.bprintf(instruction.str[:], "SKNP V%X", vx)
+					case:      fmt.bprintf(instruction.str[:], "DATA 0x%04X", opcode)
 				}
 			case 0xF:
 				switch kk {
-					case 0x07: str = fmt.tprintf("LD V%X, DT", vx)
-					case 0x0A: str = fmt.tprintf("LD V%X, K", vx)
-					case 0x15: str = fmt.tprintf("LD DT, V%X", vx)
-					case 0x18: str = fmt.tprintf("LD ST, V%X", vx)
-					case 0x1E: str = fmt.tprintf("ADD I, V%X", vx)
-					case 0x29: str = fmt.tprintf("LD F, V%X", vx)
-					case 0x33: str = fmt.tprintf("LD B, V%X", vx)
-					case 0x55: str = fmt.tprintf("LD [I], V%X", vx)
-					case 0x65: str = fmt.tprintf("LD V%X, [I]", vx)
-					case:      str = fmt.tprintf("DATA 0x%04X", opcode)
+					case 0x07: fmt.bprintf(instruction.str[:], "LD V%X, DT", vx)
+					case 0x0A: fmt.bprintf(instruction.str[:], "LD V%X, K", vx)
+					case 0x15: fmt.bprintf(instruction.str[:], "LD DT, V%X", vx)
+					case 0x18: fmt.bprintf(instruction.str[:], "LD ST, V%X", vx)
+					case 0x1E: fmt.bprintf(instruction.str[:], "ADD I, V%X", vx)
+					case 0x29: fmt.bprintf(instruction.str[:], "LD F, V%X", vx)
+					case 0x33: fmt.bprintf(instruction.str[:], "LD B, V%X", vx)
+					case 0x55: fmt.bprintf(instruction.str[:], "LD [I], V%X", vx)
+					case 0x65: fmt.bprintf(instruction.str[:], "LD V%X, [I]", vx)
+					case:      fmt.bprintf(instruction.str[:], "DATA 0x%04X", opcode)
 				}
-			case: str = fmt.tprintf("DATA 0x%04X", opcode)
+			case: fmt.bprintf(instruction.str[:], "DATA 0x%04X", opcode)
 		}
 
-		append(&entries, Instruction{address = addr, raw = opcode, str = str})
+		count += 1
 	}
 
-	return entries[:]
+	return count
 }

src/simulator/gui_status_bar.odin

@@ -5,7 +5,6 @@ import rl "vendor:raylib"
 
 StatusIconShape :: enum { CIRCLE, SQUARE }
 
-// @TODO: render status bar text
 gui_status_bar :: proc(rect: rl.Rectangle, sim: ^Simulator) {
     // Left to right text draws
     rl.DrawRectangleLinesEx(rect, 1, rl.DARKGRAY)
@@ -13,7 +12,7 @@ gui_status_bar :: proc(rect: rl.Rectangle, sim: ^Simulator) {
     cursor: f32 = rect.x + PADDING_X
     cy := rect.y + rect.height * 0.5
 
-    if sim.running && !sim.paused {
+    if !sim.paused {
         status_icon(&cursor, cy, rl.GREEN, .CIRCLE, "Running", sim.font)
     } else {
         status_icon(&cursor, cy, rl.RED, .SQUARE, "Paused", sim.font)

src/simulator/gui_tab_disasm.odin

@@ -12,6 +12,11 @@ gui_tab_disasm :: proc(rect: rl.Rectangle, sim: ^Simulator) {
     // Header: Address label
     rl.DrawTextEx(sim.font, "Disassembled Instructions", {rect.x + 4, rect.y + 4}, 18, 1, rl.WHITE)
 
+	follow_label : cstring = "Follow: ON" if sim.disasm_follow else "Follow: OFF"
+	follow_rect  := rl.Rectangle{rect.x + rect.width - 110, rect.y + 4, 100, 20}
+	if rl.GuiButton(follow_rect, follow_label) {
+		sim.disasm_follow = !sim.disasm_follow
+	}
 
     // Scroll panel area (below header)
     panel_rect := rl.Rectangle{
@@ -38,7 +43,7 @@ gui_tab_disasm :: proc(rect: rl.Rectangle, sim: ^Simulator) {
 	rl.BeginScissorMode(i32(view.x), i32(view.y), i32(view.width), i32(view.height))
 	defer rl.EndScissorMode()
 
-	for entry, i in sim.disasm {
+	for entry, i in sim.disasm[:sim.disasm_count] {
 	    y_pos := panel_rect.y + (f32(i) * LINE_HEIGHT) + sim.disasm_scroll.y
 
 		txt := fmt.tprintf("%d : %s", i, entry.str)
@@ -58,4 +63,21 @@ gui_tab_disasm :: proc(rect: rl.Rectangle, sim: ^Simulator) {
 			txt_color,
 		)
 	}
+
+	if sim.disasm_follow {
+		for entry, i in sim.disasm[:sim.disasm_count] {
+			if entry.address == sim.machine.pc {
+				target_y := f32(i) * LINE_HEIGHT
+				visible_height := panel_rect.height
+
+				// Center the active instruction in the panel
+				sim.disasm_scroll.y = -(target_y - visible_height / 2)
+
+				// Clamp so we don't scroll past the content
+				max_scroll := -(f32(sim.disasm_count) * LINE_HEIGHT - visible_height)
+				sim.disasm_scroll.y = clamp(sim.disasm_scroll.y, max_scroll, 0)
+				break
+			}
+		}
+	}
 }

src/simulator/simulator.odin

@@ -3,18 +3,32 @@ package simulator
 import emu "../machine"
 import rl "vendor:raylib"
 
+// CHIP-8 ROM can be at most 3584 bytes (4096 - 0x200 reserved)
+// Each instruction is 2 bytes, 3584 / 2 = 1792 instructions.
+MAX_INSTRUCTIONS :: 1792
+
+Instruction :: struct {
+	address: u16,
+	raw:	 u16,
+	str:     [32]u8
+}
+
 Simulator :: struct {
 	// Emulator
 	machine:		   ^emu.System,
 	rom_loaded:		   bool,
-	running:		   bool,
 	paused:			   bool,
+	step:			   bool,
 	cycles_per_second: int,
+	speed_value:	   f32,
 	// GUI
 	font:			   rl.Font,
 	active_tab:		   i32,
 	mem_scroll:        rl.Vector2,
-	disasm:		       []Instruction,
+	// disassembly props
+	disasm:		       [MAX_INSTRUCTIONS]Instruction,
+	disasm_follow:	   bool,
+	disasm_count:	   int,
 	disasm_scroll:     rl.Vector2,
 }
 
@@ -23,9 +37,10 @@ run_simulator :: proc(s: ^emu.System) {
 	sim := Simulator {
 		machine = s,
 		rom_loaded = false,
-		running = false,
 		paused = true,
-		cycles_per_second = 12
+		step = false,
+		cycles_per_second = 12,
+		disasm_follow = true
 	}
 
 	run_gui(&sim)