Cargo.toml

@@ -8,4 +8,5 @@ edition = "2021"
 [dependencies]
 bdf = "0.6.0"
 bitvec = "1.0.1"
+iced = { version = "0.12.0", features = ["canvas", "smol"] }
 minifb = "0.25.0"

src/cpu.rs

@@ -1,12 +1,14 @@
 use crate::error::{ExecutionError, GeorgeError, GeorgeErrorKind, MemoryError};
 use crate::instructions::{get_instruction, Instruction};
-use crate::memory::Mem;
+use crate::memory::{self, Mem};
 use crate::types::{Byte, Word};
-use std::path::PathBuf;
 use std::process::exit;
-use std::sync::Mutex;
 use std::time::Duration;
-use std::{str::FromStr, sync::Arc, thread::sleep};
+use std::{
+    str::FromStr,
+    sync::{Arc, RwLock},
+    thread::sleep,
+};
 
 #[derive(Clone, Copy)]
 pub enum StatusFlag {
@@ -29,13 +31,13 @@ pub struct Cpu {
     pub p: Byte,  // Status Register
     pub irq: bool,
     pub nmi: bool,
-    pub memory: Arc<Mutex<Mem>>,
+    pub memory: Arc<RwLock<Mem>>,
     pub pending_cycles: usize,
     cycle_count: usize,
 }
 
 impl Cpu {
-    pub fn new(memory: Arc<Mutex<Mem>>) -> Self {
+    pub fn new(memory: Arc<RwLock<Mem>>) -> Self {
         Cpu {
             a: 0x00,
             x: 0x00,
@@ -57,14 +59,14 @@ impl Cpu {
         Ok(())
     }
     pub fn read(&self, address: Word) -> Result<Byte, MemoryError> {
-        let memory = match self.memory.lock() {
+        let memory = match self.memory.try_read() {
             Ok(read) => read,
             Err(_) => {
                 println!("Couldn't acquire read lock on memory in cpu thread");
                 return Err(MemoryError::NoDataAtAddress);
             } // TODO: upgrade this error type to a `GeorgeError` and make an errorkind for thread lock errors
         };
-        Ok(memory.read(address))
+        memory.read(address)
     }
     pub fn read_word(&self, address: Word) -> Result<Word, MemoryError> {
         let low_byte = self.read(address)?;
@@ -93,7 +95,7 @@ impl Cpu {
 
     pub fn pop_stack(&mut self) -> Result<Byte, ExecutionError> {
         let byte = self.read(self.stack_addr())?;
-        self.s = self.s.wrapping_add(0x1);
+        self.s += 0x1;
         Ok(byte)
     }
 
@@ -119,21 +121,21 @@ impl Cpu {
     }
 
     pub fn write(&mut self, address: Word, data: Byte) -> Result<(), MemoryError> {
-        let mut memory = match self.memory.lock() {
+        let mut memory = match self.memory.write() {
             Ok(write) => write,
             Err(_) => {
                 println!("Couldn't acquire write lock on memory in cpu thread");
                 return Err(MemoryError::NoDataAtAddress);
             } // TODO: upgrade this error type to a `GeorgeError` and make an errorkind for thread lock errors
         };
-        memory.write(address, data);
+        memory.write(address, data)?;
         Ok(())
     }
 
     pub fn execute(&mut self) {
-        self.cycle();
+        self.cycle().unwrap();
         while self.pending_cycles != 0 {
-            self.cycle();
+            self.cycle().unwrap();
         }
     }
 
@@ -164,7 +166,7 @@ impl Cpu {
     //         }
     //     }
     // }
-    pub fn cycle(&mut self) {
+    pub fn cycle(&mut self) -> Result<(), GeorgeError> {
         sleep(Duration::from_nanos(100));
         if self.pending_cycles == 0 {
             if self.nmi || (self.irq && !self.get_flag(StatusFlag::IrqDisable)) {
@@ -176,11 +178,10 @@ impl Cpu {
                     match self.read_word(0xFFFA) {
                         Ok(word) => self.pc = word,
                         Err(error) => {
-                            let george_error = GeorgeError {
+                            return Err(GeorgeError {
                                 kind: GeorgeErrorKind::Memory(error),
                                 desc: String::from_str("Couldn't read NMI vector").unwrap(),
-                            };
-                            println!("{:?}", george_error.desc);
+                            })
                         }
                     };
                     self.pending_cycles = 8;
@@ -188,11 +189,10 @@ impl Cpu {
                     match self.read_word(0xFFFE) {
                         Ok(word) => self.pc = word,
                         Err(error) => {
-                            let george_error = GeorgeError {
+                            return Err(GeorgeError {
                                 kind: GeorgeErrorKind::Memory(error),
                                 desc: String::from_str("Couldn't read IRQ vector").unwrap(),
-                            };
-                            println!("{:?}", george_error.desc);
+                            })
                         }
                     };
                     self.pending_cycles = 7
@@ -204,73 +204,62 @@ impl Cpu {
             let opcode = match self.read(self.pc) {
                 Ok(byte) => byte,
                 Err(error) => {
-                    let george_error = GeorgeError {
-                        desc: format!("Failed to read from memory at address {:#06x}!", self.pc),
+                    return Err(GeorgeError {
+                        desc: String::from_str("Failed to read the program counter!").unwrap(),
                         kind: GeorgeErrorKind::Memory(error),
-                    };
-                    println!("{:?}", george_error.desc);
-                    return;
+                    })
                 }
             };
             let instruction = get_instruction(opcode);
             match instruction {
                 Instruction::Valid(valid_instruction) => {
-                    //println!("a: {a:#04x}, x: {x:#04x}, y: {y:#04x}, pc: {pc:#06x}, sp: {s:#04x}, sr: {p:#010b}, irq: {irq:?}, nmi: {nmi:?}", a = self.a, x = self.x, y = self.y, pc = self.pc, s = self.s, p = self.p, irq = self.irq, nmi = self.nmi);
-                    //println!(
-                    //    "Instruction: {:?}, {:#04x}",
-                    //    valid_instruction.opcode, opcode
-                    //);
-                    //println!("");
+                    println!("a: {a:#04x}, x: {x:#04x}, y: {y:#04x}, pc: {pc:#06x}, sp: {s:#04x}, sr: {p:#010b}, irq: {irq:?}, nmi: {nmi:?}", a = self.a, x = self.x, y = self.y, pc = self.pc, s = self.s, p = self.p, irq = self.irq, nmi = self.nmi);
+                    println!(
+                        "Instruction: {:?}, {:#04x}",
+                        valid_instruction.opcode, opcode
+                    );
+                    println!("");
                     self.pc += 1;
                     match valid_instruction.opcode.call(self) {
                         Ok(_) => {
                             self.pending_cycles += valid_instruction.cycles as usize;
-                        }
-                        Err(error) => {
-                            let george_error = GeorgeError{
+                        },
+                        Err(error) => return Err(GeorgeError{
                             desc: format!("An IncompatibleAddrMode was used at address {:#06x} for instruction {:?}", 
-                                          self.pc, valid_instruction).to_string(), kind: error};
-                            println!("{:?}", george_error.desc);
-                        }
+                                          self.pc, valid_instruction).to_string(), kind: error})
                     };
                 }
                 Instruction::Invalid(invalid_instruction) => match invalid_instruction.opcode {
                     0x02 => {
-                        let memory = match self.memory.lock() {
+                        let memory = match self.memory.try_read() {
                             Ok(read) => read,
                             Err(_) => {
                                 println!("Couldn't acquire read lock on memory in cpu thread");
-                                let george_error = GeorgeError {
+                                return Err(GeorgeError {
                                     kind: GeorgeErrorKind::Memory(MemoryError::Unwritable),
                                     desc: "Couldn't acquire read lock on memory in cpu thread"
                                         .to_string(),
-                                };
-                                println!("{:?}", george_error.desc);
-                                return;
+                                });
                             }
                         };
-
-                        println!("a: {a:#04x}, x: {x:#04x}, y: {y:#04x}, pc: {pc:#06x}, sp: {s:#04x}, sr: {p:#010b}, irq: {irq:?}, nmi: {nmi:?}", a = self.a, x = self.x, y = self.y, pc = self.pc, s = self.s, p = self.p, irq = self.irq, nmi = self.nmi);
-                        memory
-                            .dump(PathBuf::from_str("./cpu_dump.bin").unwrap())
-                            .unwrap();
+                        memory.dump().unwrap();
                         exit(1);
                     }
                     _ => {
-                        let george_error = GeorgeError {
+                        return Err(GeorgeError {
                             kind: GeorgeErrorKind::Execution(ExecutionError::InvalidInstruction),
                             desc: format!(
                         "An invalid instruction with opcode {:#04x} was called at address {:#06x}",
                         invalid_instruction.opcode, self.pc
                     ),
-                        };
-                        println!("{:?}", george_error.desc);
+                        });
                     }
                 },
             }
         }
         self.pending_cycles -= 1;
         self.cycle_count += 1;
+        Ok(())
     }
 
     pub fn stop(&mut self) {

src/george.asm

@@ -1,27 +1,65 @@
 .setcpu "65C02"
-.include "macro.inc"
+.segment "CODE"
 
 ; okay so rn i wanna set up a very basic system init, and write a few subroutines to draw characters at x,y coordinates
-n = $01 ; temporary storage for data stack operations
+    n = $01 ; temporary storage for data stack operations
 
-key_row = $200 ; used for character lookup when key pressed
-key_col = $201
-cursor = $202
+.macro breakpoint ; $02 isn't a valid instruction, the emulator will see this and halt, dump memory contents
+    .byte $02
+.endmacro 
 
-kb_row0 = $4400 ; keyboard hardware register, there are 5 more but i can just increment from here
+.macro pop ; drops a stack cell
+    inx
+    inx
+.endmacro
 
-.segment "ROM"
+.macro pop2 ; drops 2 data stack cells
+    inx
+    inx
+    inx
+    inx
+.endmacro
 
-reset:
+.macro push ; 
+    dex
+    dex
+.endmacro
+
+.macro push2 ; 
+    dex
+    dex
+    dex
+    dex
+.endmacro
+
+.macro to_r ; pop the top of the stack off and save it in the return (hardware) stack: (n -- )
+    lda 1, x
+    pha
+    lda 0, x
+    pha
+    pop
+.endmacro
+
+.macro from_r ; pop the top of the return stack off and put it on the data stack: ( -- n)
+    push
+    pla
+    sta 0, x
+    pla
+    sta 1, x
+.endmacro
+
+init:
     ldx #0; initialize data stack pointer
-;lda #$80
-;sta $200
-;adc $200
-;breakpoint
+    jsr initdisplay
+
+main:
+    jsr draw
 
 initdisplay:
     lda #$20
     ldy #0
+    jsr cleardisplay
+    rts
 
 cleardisplay:
     sta $6000,y
@@ -34,104 +72,27 @@ cleardisplay:
     sta $6700,y ; this goes slightly over but it's fine
     iny
     bne cleardisplay
-
-main:
-    ;jsr draw
-    jsr keyboard
-    jmp main
-
-keyboard:
-    ldy #0 ; loop through each row
-    @loop:
-        lda kb_row0, y
-        beq @skip ; if row has no key pressed, skip checking which key
-        jsr key_pressed
-        @skip:
-            iny
-            cpy #5
-            bne @loop
     rts
 
-key_pressed: ; a is loaded with the row byte
-    sty key_row ; store character row
-    inc cursor
-    pha
-    phy
-    ldy #0
-    @find_col:            ; test each row bit, store column if key pressed
-        lsr                ; test bit 7
-        bcs store_col       ; if set, go store character column
-        iny
-        cpy #8
-        bne @find_col     ; loop until we've checked each bit
-
-store_col:
-    sty key_col
-
-keymap_index:
+draw: ; draw a character at (20, 30)
+    lda #63
     push
-    lda key_col
-    stz 1, x
-    sta 0, x
+    sta 0, x ; low byte
+    stz 1,x ; high byte is zero
+    lda #28
     push
-    lda #8
-    stz 1, x
-    sta 0, x
-    push
-    lda key_row
-    stz 1, x
-    sta 0, x
-    jsr mult
-    jsr plus
-    lda 0, x
-    tay
-
-do_something_w_key: ; we've stored the character position, now let's 
-    lda keymap, y
-    ldy cursor
-    sta $6000, y
-    pla
-    ply
-    rts
-
-keymap:
-    .byte "?outrew?"
-    .byte "?piygsq?"
-    .byte "a??khvd?"
-    .byte "42ljbfz?"
-    .byte "31?mncx?"
-    .byte "?????ssm"
-
-draw:
-;    lda #%01000000
-;    bit $4400
-;    beq @1
-;    push_coords #0, #0
-;    push_char #$77
-;    jsr draw_char
-;    @1: 
-;    lda #%00100000
-;    bit $4400
-;    beq @2
-;    push_coords #0, #0
-;    push_char #$65
-;    jsr draw_char
-;    @2: 
-    rts
-
-draw_char: ; draw a character c at (x, y) (n1: x n2: y n3: c -- )
-    lda 0, x ; load a with character to draw
-    pop ; and pop it off the stack
+    sta 0,x ; same here
+    stz 1,x
     jsr get_char_address ; calculate where to put the character in memory
+    lda #4
     sta (0, x) ; store a at the address pointed to on the stack
-    rts
+    brk
 
 get_char_address:   ; gets vram address for a character at (x, y),
                     ; (n1: x n2: y -- n: $6000 + x + (64 * y))
     ;jsr push_lit ; push 64 onto stack, low byte first
     ;.byte 64
     ;.byte 0
-    pha
     lda #64
     push ; doing this instead until `push_lit` is fixed
     sta 0, x
@@ -148,14 +109,18 @@ get_char_address:   ; gets vram address for a character at (x, y),
     stz 0, x
     jsr plus ; add vram start address to result
 
-    pla
     rts
-
-fill: ; fills an area from (x1, y1) to (x2, y2) will character c, (n1: c n2: x1 n3: y1 n4: x2 n5: y2 -- )
     
-    jsr get_char_address
+; inc16
+; add 1 to a 16-bit pointer in zero page
+
+;inc16:
+;    inc ptr
+;    bne :+
+;    inc ptr+1
+;:   rts
+;
 
-; --- Data Stack --- ;
 ; on this channel we love garth wilson: https://wilsonminesco.com/stacks/StackOps.ASM
 ; data stack is built up of 2-byte cells
 
@@ -233,8 +198,6 @@ mult: ; multiply: (n1 n2 -- n1*n2), frankly, i don't know how this works, but TO
     pop
     ply
     rts
+        
 
-
-.segment "VECTOR"
-.word reset
-
+.segment "VRAM"

src/george.config

@@ -1,10 +1,12 @@
 MEMORY {
-        RAM: start = $0000, size = $8000, type = ro, fill = yes;
-        ROM: start = $8000, size = $7FFC, type = ro, fill = yes;
-        VECTOR: start = $FFFC, size = $4, type = ro, fill = yes;
+        RAM: start = $0000, size = $0200, type = rw, fill = true;
+        PROGRAM: start = $0200, size = $3E00, type = rw, fill = true;
+        CTRL: start = $4000, size = $2000, type = rw, fill = true;
+        VRAM: start = $6000, size = $8000, type = rw, fill = true;
+        ROM: start = $E000, size = $2000, type = ro, fill = true;
     }
 
 SEGMENTS {
-        ROM: load = "ROM", type = ro;
-        VECTOR: load = "VECTOR", type = ro;
+        CODE: load = "PROGRAM", type = rw;
+        VRAM: load = "VRAM", type = rw;
     }

src/georgeencoding.txt

@@ -7,10 +7,10 @@
 #		 column #2 is the Unicode (in hex as 0xXXXX)
 #		 column #3 the Unicode name (follows a comment sign, '#')
 
-0x00    0x00	# 
-0x01	0x2591  # 
-0x02	0x2592  # ᴥ
-0x03	0x2593  # ʔ
+0x00	0x0295	# ʕ
+0x01	0x00B7  # Middle Dot
+0x02	0x1D25	# ᴥ
+0x03	0x0294	# ʔ
 0x04	0x2661	# White heart 
 0x05    0x2665	# Black heart 
 0x06	0x2B50	# White star
@@ -189,70 +189,70 @@
 0xB3	0x258D	#	
 0xB4	0x258E	#	
 0xB5	0x258F	#	
-0xB6    0x0295  #	
-0xB7    0x00B7  #	
-0xB8    0x1D25  #	
-0xB9	0x0294
-0xBA	0x2596  
-0xBB	0x2597  
-0xBC	0x2598  
-0xBD	0x2599  
-0xBE	0x259A  
-0xBF	0x259B  
-0xC0	0x259C  
-0xC1	0x259D	
-0xC2	0x259E	
-0xC3    0x259F	
-0xC4	0x2190	
-0xC5	0x2191	
-0xC6	0x2192	
-0xC7	0x2193	
-0xC8	0x2B60	
-0xC9	0x2B61	
-0xCA	0x2B62	
-0xCB	0x2B63	
-0xCC	0x2B80  
-0xCD	0x2B81  
-0xCE	0x2B82  
-0xCF	0x2B83  
-0xD0	0xF049	
-0xD1	0xF04A	
-0xD2	0x23F3	
-0xD3	0xF07B	
-0xD4	0xF07C	
-0xD5	0xF114	
-0xD6	0xF115	
-0xD7	0xF250	
-0xD8	0xF251	
-0xD9	0xF253	
-0xDA	0xF254	
-0xDB	0xF461	
-0xDC	0xF016	
-0xDD	0xF401	
-0xDE	0x1F52E	
-0xDF	0xF2DB	
-0xE0	0xF008	
-0xE1	0x25C7	
-0xE2	0x25C8	
-0xE3	0x1F311	
-0xE4	0x1F312	
-0xE5	0x1F313	
-0xE6	0x1F314	
-0xE7	0x1F315	
-0xE8	0x1F316	
-0xE9	0x1F317	
-0xEA	0x1F318	
-0xEB	0xF04C	
-0xEC	0x2714	
-0xED	0x2718	
-0xEE	0x25C6	
-0xEF	0xF15D	
-0xF0	0xF15E	
-0xF1	0xF071	
-0xF2	0xF449	
-0xF3	0xF529	
-0xF4	0xF658	
-0xF5	0xF659 		#
+0xB6    0x2591	#	
+0xB7    0x2592	#	
+0xB8    0x2593  #	
+0xB9	0x2596  # 
+0xBA	0x2597  # 
+0xBB	0x2598  #
+0xBC	0x2599  # 
+0xBD	0x259A  # 
+0xBE	0x259B  #
+0xBF	0x259C  # 
+0xC0	0x259D	#	
+0xC1	0x259E	#	
+0xC2	0x259F	#
+0xC3    0x2190	#	
+0xC4	0x2191	#   
+0xC5	0x2192	#   
+0xC6	0x2193	#	
+0xC7	0x2B60	#	
+0xC8	0x2B61	#	
+0xC9	0x2B62	#	
+0xCA	0x2B63	#   
+0xCB	0x2B80  #
+0xCC	0x2B81  #
+0xCD	0x2B82  #
+0xCE	0x2B83  #
+0xCF	0xF049	#
+0xD0	0xF04A	#
+0xD1	0x23F3	#
+0xD2	0xF07B	#
+0xD3	0xF07C	#
+0xD4	0xF114	#
+0xD5	0xF115	#
+0xD6	0xF250	#
+0xD7	0xF251	#
+0xD8	0xF253	#
+0xD9	0xF254	#
+0xDA	0xF461	#
+0xDB	0xF016	#
+0xDC	0xF401	#
+0xDD	0x1F52E	#
+0xDE	0xF2DB	#
+0xDF	0xF008	#
+0xE0	0x25C7	#
+0xE1	0x25C8	#
+0xE2	0x1F311	#
+0xE3	0x1F312	#
+0xE4	0x1F313	#
+0xE5	0x1F314	#
+0xE6	0x1F315	#
+0xE7	0x1F316	#
+0xE8	0x1F317	#
+0xE9	0x1F318	#
+0xEA	0xF04C	#
+0xEB	0x2714	#
+0xEC	0x2718	#
+0xED	0x25C6	#
+0xEE	0xF15D	#
+0xEF	0xF15E	#
+0xF0	0xF071	#
+0xF1	0xF449	#
+0xF2	0xF529	#
+0xF3	0xF658	#
+0xF4	0xF659 	#
+0xF5	0x0020	#
 0xF6	0x1f381	#	Space
 0xF7	0xf05a	#	Space
 0xF8	0xf06a	#	Space

src/instructions.rs

@@ -2063,7 +2063,6 @@ impl Opcode {
                     let byte = cpu.read(address.try_into()?)?;
                     let carry = cpu.get_flag(StatusFlag::Carry);
                     let result = cpu.a as Word + byte as Word + carry as Word;
-                    println!("{result:#04x}");
                     cpu.set_flag(StatusFlag::Carry, result > Word::from(u8::max_value()));
                     cpu.set_flag(StatusFlag::Zero, result as Byte == 0);
                     cpu.set_flag(
@@ -2074,7 +2073,6 @@ impl Opcode {
                     );
                     cpu.set_flag(StatusFlag::Negative, cpu.is_negative(result as Byte));
                     cpu.a = result as Byte;
-                    println!("{:#04x}", cpu.a);
                     Ok(())
                 }
                 _ => Err(GeorgeErrorKind::AddrMode(
@@ -2105,7 +2103,10 @@ impl Opcode {
                 fn asl(cpu: &mut Cpu, value: Byte) -> Byte {
                     cpu.set_flag(StatusFlag::Carry, value & 0b1000_0000 == 0b1000_0000);
                     let shifted_value = value << 1;
-                    cpu.set_flag(StatusFlag::Negative, cpu.is_negative(shifted_value));
+                    cpu.set_flag(
+                        StatusFlag::Negative,
+                        value & StatusFlag::Negative as Byte > 0,
+                    );
                     cpu.set_flag(StatusFlag::Zero, shifted_value == 0);
                     shifted_value
                 }
@@ -2531,8 +2532,7 @@ impl Opcode {
             Opcode::BRK(mode) => match mode {
                 AddressingMode::Implied => {
                     cpu.set_flag(StatusFlag::Brk, true);
-                    Ok(())
-                    //panic!("Interrupts unimplemented!");
+                    panic!("Interrupts unimplemented!");
                 }
                 _ => Err(GeorgeErrorKind::AddrMode(
                     AddressingModeError::IncompatibleAddrMode,
@@ -2662,8 +2662,6 @@ impl Opcode {
             Opcode::DEX(mode) => match mode {
                 AddressingMode::Implied => {
                     cpu.x = cpu.x.wrapping_sub(1);
-                    cpu.set_flag(StatusFlag::Zero, cpu.x == 0);
-                    cpu.set_flag(StatusFlag::Negative, cpu.is_negative(cpu.x));
                     Ok(())
                 }
                 _ => Err(GeorgeErrorKind::AddrMode(
@@ -2672,9 +2670,7 @@ impl Opcode {
             },
             Opcode::DEY(mode) => match mode {
                 AddressingMode::Implied => {
-                    cpu.y = cpu.y.wrapping_sub(1);
-                    cpu.set_flag(StatusFlag::Zero, cpu.y == 0);
-                    cpu.set_flag(StatusFlag::Negative, cpu.is_negative(cpu.y));
+                    cpu.y -= 1;
                     Ok(())
                 }
                 _ => Err(GeorgeErrorKind::AddrMode(
@@ -2828,8 +2824,11 @@ impl Opcode {
                 fn lsr(cpu: &mut Cpu, value: Byte) -> Byte {
                     cpu.set_flag(StatusFlag::Carry, value & 1 == 1);
                     let shifted_value = value >> 1;
+                    cpu.set_flag(
+                        StatusFlag::Negative,
+                        value & StatusFlag::Negative as Byte > 0,
+                    );
                     cpu.set_flag(StatusFlag::Zero, shifted_value == 0);
-                    cpu.set_flag(StatusFlag::Negative, cpu.is_negative(value));
                     shifted_value
                 }
                 match mode {
@@ -3049,7 +3048,10 @@ impl Opcode {
                     let carry = cpu.get_flag(StatusFlag::Carry) as Byte;
                     cpu.set_flag(StatusFlag::Carry, value >> 7 == 1);
                     let shifted_value = (value << 1) + carry;
-                    cpu.set_flag(StatusFlag::Negative, cpu.is_negative(shifted_value));
+                    cpu.set_flag(
+                        StatusFlag::Negative,
+                        shifted_value & StatusFlag::Negative as Byte > 0,
+                    );
                     cpu.set_flag(StatusFlag::Zero, shifted_value == 0);
                     shifted_value
                 }
@@ -3078,7 +3080,10 @@ impl Opcode {
                     let carry = cpu.get_flag(StatusFlag::Carry) as Byte;
                     cpu.set_flag(StatusFlag::Carry, value & 1 == 1);
                     let shifted_value = (value >> 1) + (carry << 7);
-                    cpu.set_flag(StatusFlag::Negative, cpu.is_negative(shifted_value));
+                    cpu.set_flag(
+                        StatusFlag::Negative,
+                        shifted_value & StatusFlag::Negative as Byte > 0,
+                    );
                     cpu.set_flag(StatusFlag::Zero, shifted_value == 0);
                     shifted_value
                 }

src/main.rs

@@ -3,23 +3,35 @@
 mod cpu;
 mod error;
 mod instructions;
-mod keyboard;
 mod memory;
 mod types;
 mod video;
 
 use crate::cpu::Cpu;
-use crate::memory::Mem;
+use crate::memory::{Mem, MemMappedDevice};
 use crate::video::Crtc;
 
-use std::str::FromStr;
-use std::sync::Mutex;
-use std::thread::sleep;
-use std::time::Duration;
-use std::{path::PathBuf, sync::Arc, thread};
+use std::{
+    path::PathBuf,
+    sync::{Arc, RwLock},
+    thread,
+};
 
 fn main() {
-    let mut memory = Mem::new();
+    let ram = MemMappedDevice::new(0x0000, 0x3FFF, 2, "ram".into());
+    let control = MemMappedDevice::new(0x4000, 0x5FFF, 4, "control".into());
+    let vram = MemMappedDevice::new(0x6000, 0xDFFF, 1, "vram".into());
+    let rom = MemMappedDevice::new(0xE000, 0xFFFF, 4, "rom".into());
+    let mut memory = Mem::new(ram);
+    if let Err(error) = memory.add_area(control) {
+        println!("Error adding vram: {:?}", error.desc);
+    };
+    if let Err(error) = memory.add_area(vram) {
+        println!("Error adding vram: {:?}", error.desc);
+    };
+    if let Err(error) = memory.add_area(rom) {
+        println!("Error adding rom: {:?}", error.desc);
+    };
     let binary = match std::fs::File::open(PathBuf::from(
         "/Users/kline/projects/winter/george-emu/src/george",
     )) {
@@ -29,20 +41,20 @@ fn main() {
     if let Err(error) = memory.read_from_bin(binary) {
         println!("{:?}", error);
     };
+    memory.write(0xFFFC, 0x00).unwrap();
+    memory.write(0xFFFD, 0x02).unwrap();
 
-    memory
-        .dump(PathBuf::from_str("./coredump.bin").unwrap())
-        .unwrap();
-
-    let shared_memory = Arc::new(Mutex::new(memory));
+    let shared_memory = Arc::new(RwLock::new(memory));
     let cpu_memory = shared_memory.clone();
     let display_memory = shared_memory.clone();
 
+    let mut screen = Crtc::new(display_memory);
+
     thread::spawn(move || {
         let mut cpu = Cpu::new(cpu_memory);
         cpu.reset().unwrap();
         cpu.execute();
     });
-    let mut screen = Crtc::new(display_memory);
     screen.run();
+    shared_memory.write().unwrap().dump().unwrap();
 }

src/memory.rs

@@ -1,44 +1,124 @@
-use crate::error::MemoryError;
+use crate::error::{GeorgeError, GeorgeErrorKind, MappingError, MemoryError};
 use crate::types::{Byte, Word};
 use std::io::{self, Write};
 use std::path::PathBuf;
-use std::u16;
 use std::{fs::File, io::Read};
 
+#[derive(Debug, Clone)]
+pub struct MemMappedDevice {
+    start: Word,
+    end: Word,
+    pages: usize,
+    page: usize,
+    data: Vec<Byte>,
+    label: String,
+}
+
+impl MemMappedDevice {
+    pub fn new(start: Word, end: Word, pages: usize, label: String) -> Self {
+        Self {
+            start,
+            end,
+            pages,
+            page: 0,
+            data: vec![0x00; (end as usize + 1 - start as usize) * pages],
+            label,
+        }
+    }
+    fn contains(&self, address: Word) -> bool {
+        self.start <= address && self.end >= address
+    }
+    fn swap_page(&mut self, page: usize) -> Result<(), GeorgeError> {
+        match page > self.pages {
+            true => Err(GeorgeError {
+                kind: GeorgeErrorKind::Memory(MemoryError::Unmapped), //TODO: should be MappingError::InvalidPage,
+                desc: format!(
+                    "{:?} tried to swap to a page outside of its range",
+                    self.label
+                ),
+            }),
+            false => {
+                self.page = page;
+                Ok(())
+            }
+        }
+    }
+    fn size(&self) -> Word {
+        self.end - self.start + 1
+    }
+    fn translate_address(&self, address: Word) -> Word {
+        (address - self.start) + self.size() * (self.page as Word)
+    } // This needs to translate memory address from CPU land to local land, so
+      // for rom an address like 0xFFFF needs to be translated to Page X, 0xFFF
+}
+
 #[derive(Debug, Clone)]
 pub struct Mem {
-    pub data: Vec<Byte>,
+    areas: Vec<MemMappedDevice>,
 }
 
 impl Mem {
-    pub fn new() -> Self {
-        Self {
-            data: vec![0; u16::MAX as usize + 1],
-        }
+    pub fn new(area: MemMappedDevice) -> Self {
+        Self { areas: vec![area] }
     }
-    pub fn dump(&self, path: PathBuf) -> io::Result<()> {
-        let mut outfile = File::create(path)?;
-        outfile.write_all(&self.data)?;
+    pub fn dump(&self) -> io::Result<()> {
+        let mut outfile = File::create("./coredump.bin")?;
+        let mut data = Vec::new();
+        for area in &self.areas {
+            for byte in &area.data {
+                data.push(byte.to_owned());
+            }
+        }
+        outfile.set_len(0xFFFF)?;
+        outfile.write_all(&data)?;
         Ok(())
     }
-
-    pub fn read(&self, address: Word) -> Byte {
-        self.data[address as usize]
+    pub fn add_area(&mut self, area: MemMappedDevice) -> Result<(), GeorgeError> {
+        for existing_area in &self.areas {
+            if existing_area.contains(area.end) || existing_area.contains(area.start) {
+                return Err(GeorgeError {
+                    desc: format!(
+                        "Tried to assign an area already allocated to {:?}",
+                        existing_area
+                    ),
+                    kind: GeorgeErrorKind::Mapping(MappingError::RegionOccupied),
+                });
+            }
+        }
+        self.areas.push(area);
+        Ok(())
+    }
+    pub fn read(&self, address: Word) -> Result<Byte, MemoryError> {
+        for area in &self.areas {
+            if area.contains(address) {
+                let translated_address = area.translate_address(address);
+                match area.data.get(translated_address as usize) {
+                    Some(data) => return Ok(*data),
+                    None => return Err(MemoryError::NoDataAtAddress),
+                }
+            }
+        }
+        Err(MemoryError::Unmapped)
     }
 
-    pub fn write(&mut self, address: Word, data: Byte) {
-        self.data[address as usize] = data;
+    pub fn write(&mut self, address: Word, data: Byte) -> Result<(), MemoryError> {
+        for area in self.areas.iter_mut() {
+            if area.contains(address) {
+                // println!("Writing to area {label}", label = area.label);
+                let translated_address = area.translate_address(address);
+                area.data[translated_address as usize] = data;
+                return Ok(());
+            };
+        }
+        Err(MemoryError::Unmapped)
     }
 
     pub fn read_from_bin(&mut self, f: File) -> Result<(), MemoryError> {
         let bytes = f.bytes();
         for (address, byte) in bytes.enumerate() {
             match byte {
-                Ok(value) => self.write(address as Word, value),
-                Err(_) => {
-                    println!("couldn't write byte {:#04x}", address);
-                    return Err(MemoryError::Unwritable);
-                }
+                Ok(value) => self.write(address as Word, value)?,
+                Err(_) => return Err(MemoryError::Unwritable),
             }
         }
         Ok(())

src/video.rs

@@ -3,7 +3,7 @@ use minifb::{Key, Scale, ScaleMode, Window, WindowOptions};
 use std::{
     fs::File,
     io::Read,
-    sync::{Arc, Mutex},
+    sync::{Arc, RwLock},
     thread::sleep,
     time::{Duration, Instant},
 };
@@ -12,7 +12,7 @@ const FG_COLOR: u32 = 0xFFCC00;
 const BG_COLOR: u32 = 0x110500;
 
 pub struct Crtc {
-    memory: Arc<Mutex<Mem>>,
+    memory: Arc<RwLock<Mem>>,
     buffer: Vec<u32>,
     window: minifb::Window,
     char_rom: Vec<u8>,
@@ -26,7 +26,7 @@ pub fn get_char_bin(path: &str) -> Vec<u8> {
 }
 
 impl Crtc {
-    pub fn new(memory: Arc<Mutex<Mem>>) -> Self {
+    pub fn new(memory: Arc<RwLock<Mem>>) -> Self {
         let window = Window::new(
             "ʕ·ᴥ·ʔ-☆",
             512,
@@ -52,127 +52,82 @@ impl Crtc {
         }
     }
     fn draw(&mut self) {
-        let memory = match self.memory.lock() {
-            Ok(memory) => memory,
+        match &mut self.memory.clone().try_read() {
+            Ok(memory) => {
+                let hw_ctrl = memory.read(0x4000).unwrap();
+                match hw_ctrl & 0b0000_1000 == 0b0000_1000 {
+                    false => self.draw_chars(),
+                    true => self.draw_hires(),
+                };
+            }
             Err(_) => {
-                println!("Couldn't acquire read on shared memory in video thread");
+                println!("Couldn't acquire read on shared memory in main thread");
                 return;
             }
         };
-        let hw_ctrl = memory.read(0x4000);
-        match hw_ctrl & 0b0000_1000 == 0b0000_1000 {
-            false => {
-                // the rest of this function is arcane wizardry based on the specifics of george's weird
-                // display and characters... don't fuck around w it
-                let mut i = 0;
-                for char_row in 0..29 {
-                    for char_col in 0..64 {
-                        let ascii = memory.read(0x6000 + i);
-                        i += 1;
-                        for row in 0..13 {
-                            let byte = self.char_rom[ascii as usize + (row * 0x101)];
-                            for i in (0..8).rev() {
-                                let buffer_index =
-                                    ((char_row) * 13 + (row)) * 512 + (char_col * 8 + i);
-                                if (byte << i) & 0x80 == 0x80 {
-                                    self.buffer[buffer_index] = FG_COLOR;
-                                } else {
-                                    self.buffer[buffer_index] = BG_COLOR;
-                                }
-                            }
-                        }
-                    }
-                }
-            }
-            true => {
-                for addr in 0x6000..0xBF00 {
-                    // TODO: eventually this will access memory in the weird interleaved way the hardware is
-                    // designed, but this is easiest to implement for now
-                    let byte = memory.read(addr);
-                    for i in 0..8 {
-                        match byte & 0x80 >> i == 0 {
-                            true => self.buffer[(addr - 0x6000) as usize * 8 + i] = BG_COLOR,
-                            false => self.buffer[(addr - 0x6000) as usize * 8 + i] = FG_COLOR,
-                        }
-                    }
-                }
-            }
-        };
 
         self.window
             .update_with_buffer(&self.buffer, 512, 380)
             .unwrap();
     }
 
+    fn draw_chars(&mut self) {
+        let memory = match self.memory.try_read() {
+            Ok(read) => read,
+            Err(_) => {
+                println!("Couldn't acquire read on shared memory in main thread");
+                return;
+            }
+        };
+
+        // the rest of this function is arcane wizardry based on the specifics of george's weird
+        // display and characters... don't fuck around w it
+        let mut i = 0;
+        for char_row in 0..29 {
+            for char_col in 0..64 {
+                let ascii = memory.read(0x6000 + i).unwrap();
+                i += 1;
+                for row in 0..13 {
+                    let byte = self.char_rom[ascii as usize + (row * 0x101)];
+                    for i in (0..8).rev() {
+                        let buffer_index = ((char_row) * 13 + (row)) * 512 + (char_col * 8 + i);
+                        if (byte << i) & 0x80 == 0x80 {
+                            self.buffer[buffer_index] = FG_COLOR;
+                        } else {
+                            self.buffer[buffer_index] = BG_COLOR;
+                        }
+                    }
+                }
+            }
+        }
+    }
+    fn draw_hires(&mut self) {
+        let memory = match self.memory.try_read() {
+            Ok(read) => read,
+            Err(_) => {
+                println!("Couldn't acquire read on shared memory in main thread");
+                return;
+            }
+        };
+        for addr in 0x6000..0xBF00 {
+            // TODO: eventually this will access memory in the weird interleaved way the hardware is
+            // designed, but this is easiest to implement for now
+            let byte = memory.read(addr).unwrap();
+            for i in 0..8 {
+                match byte & 0x80 >> i == 0 {
+                    true => self.buffer[(addr - 0x6000) as usize * 8 + i] = BG_COLOR,
+                    false => self.buffer[(addr - 0x6000) as usize * 8 + i] = FG_COLOR,
+                }
+            }
+        }
+    }
     pub fn run(&mut self) {
         let frame_duration = Duration::from_millis(16);
         let mut previous_draw = Instant::now();
 
         loop {
-            let mut row0 = 0;
-            let mut row1 = 0;
-            let mut row2 = 0;
-            let mut row3 = 0;
-            let mut row4 = 0;
-            let mut row5 = 0;
-
-            self.window.get_keys().iter().for_each(|key| match key {
-                Key::Escape => row0 ^= 0b1000_0000,
-                Key::W => row0 ^= 0b0100_0000,
-                Key::E => row0 ^= 0b0010_0000,
-                Key::R => row0 ^= 0b0001_0000,
-                Key::T => row0 ^= 0b0000_1000,
-                Key::U => row0 ^= 0b0000_0100,
-                Key::O => row0 ^= 0b0000_0010,
-                Key::Backspace => row0 ^= 0b0000_0001,
-                Key::Tab => row1 ^= 0b1000_0000,
-                Key::Q => row1 ^= 0b0100_0000,
-                Key::S => row1 ^= 0b0010_0000,
-                Key::G => row1 ^= 0b0001_0000,
-                Key::Y => row1 ^= 0b0000_1000,
-                Key::I => row1 ^= 0b0000_0100,
-                Key::P => row1 ^= 0b0000_0010,
-                Key::Enter => row1 ^= 0b0000_0001,
-                Key::LeftShift | Key::RightShift => row2 ^= 0b1000_0000,
-                Key::D => row2 ^= 0b0100_0000,
-                Key::V => row2 ^= 0b0010_0000,
-                Key::H => row2 ^= 0b0001_0000,
-                Key::K => row2 ^= 0b0000_1000,
-                Key::Apostrophe => row2 ^= 0b0000_0100,
-                Key::Slash => row2 ^= 0b0000_0010,
-                Key::A => row2 ^= 0b0000_0001,
-                Key::LeftCtrl | Key::RightCtrl => row3 ^= 0b1000_0000,
-                Key::Z => row3 ^= 0b0100_0000,
-                Key::F => row3 ^= 0b0010_0000,
-                Key::B => row3 ^= 0b0001_0000,
-                Key::J => row3 ^= 0b0000_1000,
-                Key::L => row3 ^= 0b0000_0100,
-                Key::Key2 => row3 ^= 0b0000_0010,
-                Key::Key4 => row3 ^= 0b0000_0001,
-                Key::LeftAlt | Key::RightAlt => row4 ^= 0b1000_0000,
-                Key::X => row4 ^= 0b0100_0000,
-                Key::C => row4 ^= 0b0010_0000,
-                Key::N => row4 ^= 0b0001_0000,
-                Key::M => row4 ^= 0b0000_1000,
-                Key::Comma => row4 ^= 0b0000_0100,
-                Key::Key1 => row4 ^= 0b0000_0010,
-                Key::Key3 => row4 ^= 0b0000_0001,
-                Key::LeftSuper => row5 ^= 0b1000_0000,
-                Key::Space => row5 ^= 0b0100_0000,
-                Key::RightSuper => row5 ^= 0b0010_0000,
-                _ => {}
-            });
-
-            match &mut self.memory.lock() {
-                Ok(memory) => {
-                    memory.write(0x4400, row0);
-                    memory.write(0x4401, row1);
-                    memory.write(0x4402, row2);
-                    memory.write(0x4403, row3);
-                    memory.write(0x4404, row4);
-                    memory.write(0x4405, row5);
-                }
-                Err(error) => println!("{error}"),
+            if self.window.is_key_down(Key::Q) {
+                return;
             }
             let now = Instant::now();
             if now - previous_draw > frame_duration {