Illegal

Cargo.toml

@@ -30,7 +30,7 @@
 name = "mos6502"
 description = "A MOS 6502 Emulator"
 license = "BSD-3-Clause"
-version = "0.6.2"
+version = "0.6.3"
 authors = ["The 6502-rs Developers"]
 exclude = ["examples/**"]
 edition = "2024"

README.md

@@ -49,7 +49,7 @@ fn main() {
         0x4c, 0x12, 0x00, // Jump to .algo_
         // .end
         0xa5, 0x00,       // Load from S to A
-        0xff,
+        0x02,             // JAM - halt CPU to end program
         // .swap
         0xa6, 0x00,       // load F to X
         0xa4, 0x01,       // load S to Y

examples/asm/euclid/euclid.ca65

@@ -1,33 +1,25 @@
 ; euclid.ca65
 ; A program to find the greatest common divisor of two numbers
 
-.ORG $1000
+.segment "CODE"
 
-; .algo
-LDA $00    ; Load from F to A
-; .algo_
-SEC        ; Set carry flag
-SBC $01    ; Subtract S from the number in A (from F)
-BEQ end    ; Jump to .end if the difference is zero
-BMI swap   ; Jump to .swap if the difference is negative
-STA $00    ; Load A to F
-JMP algo_  ; Jump to .algo_
+algo:
+    LDA $00       ; Load from F to A
+algo_:
+    SEC           ; Set carry flag
+    SBC $01       ; Subtract S from A
+    BEQ end       ; Jump to end if zero
+    BMI swap      ; Jump to swap if negative
+    STA $00       ; Store A to F
+    JMP algo_     ; Continue algorithm
 
-; .end
 end:
-LDA $00    ; Load from F to A
-BRK        ; Break (end program)
+    LDA $00       ; Load result to A
+    .byte $02     ; JAM - halt CPU
 
-; .swap
 swap:
-LDX $00    ; Load F to X
-LDY $01    ; Load S to Y
-STX $01    ; Store X to S
-STY $00    ; Store Y to F
-JMP algo   ; Jump to .algo
-
-algo:
-JMP algo   ; Infinite loop to prevent program from ending
-
-algo_:
-JMP algo_  ; Infinite loop to prevent program from ending
+    LDX $00       ; Load F to X
+    LDY $01       ; Load S to Y
+    STX $01       ; Store X to S
+    STY $00       ; Store Y to F
+    JMP algo      ; Restart algorithm

examples/asm/linker.cfg

@@ -1,32 +1,18 @@
 # Linker configuration for cc65 (ld65)
-# Defines memory layout and segment placement for 6502 programs
+# Outputs raw binary containing only the code segment
 
 MEMORY {
-    # RAM: 32KB from $0000-$7FFF
-    # Used for zero page, stack, data, and code in this emulator config
-    RAM: start = $0000, size=$8000, type = rw, fill = yes, fillval = $FF, file = %O;
-
-    # ROM: Almost 32KB from $8000-$FFF9
-    # Defined but not used in examples (code runs from RAM instead)
-    ROM: start = $8000, size=$7FFA, type = ro, fill = yes, fillval = $FF, file = %O;
-
-    # ROM_VECTORS: 6 bytes at $FFFA-$FFFF
-    # Holds the three 16-bit interrupt vectors: NMI, RESET, IRQ
-    ROM_VECTORS: start = $FFFA, size=6, type = ro, fill = yes, fillval = $FF, file = %O;
+    # Code region starting at $0010, matching README examples
+    CODE: start = $0010, size = $1000, type = rw, file = %O;
 }
 
 SEGMENTS {
-    # Zero page ($00-$FF): Fast access variables
-    ZEROPAGE: load=RAM, type=rw;
-
-    # Data segment: Starts at $0200 (page 2)
-    # Page 1 ($0100-$01FF) is reserved for the stack
-    DATA: load=RAM, type=rw, offset=$0200;
+    # Code segment: Contains the program
+    CODE: load = CODE, type = ro;
 
-    # Code segment: Starts at $0400 (page 4)
-    # Leaves room for zero page, stack, and data
-    CODE: load=RAM, type=rw, offset=$0400;
-
-    # Interrupt vectors at top of memory
-    VECTORS: load=ROM_VECTORS, type=ro;
-}
+    # Optional segments
+    ZEROPAGE: load = CODE, type = rw, optional = yes;
+    DATA: load = CODE, type = rw, optional = yes;
+    RODATA: load = CODE, type = rw, optional = yes;
+    BSS: load = CODE, type = rw, optional = yes;
+}