Refactors the print flags to use bitwise flags and collect them all under a single byte (now know as the Console Flags)

.vscode/launch.json

@@ -60,7 +60,7 @@
                     "kind": "bin"
                 }
             },
-            "args": ["simple_test_machine\\programs\\hello.bin"],
+            "args": ["simple_test_machine\\programs\\hello.rw"],
             "cwd": "${workspaceFolder}"
         },
     ]

simple_test_machine/programs/hello.asm

@@ -6,8 +6,9 @@
 ; Adapted for the RE6502 emulator simple test machine
 ; compile with win2c64 using the -R option
 
-strout          .equ   $1100   ; console output address
-print_flag      .equ   $009E   ; str print flag address
+strout          .equ    $1100   ; console output address
+con_flags       .equ    $009A   ; console flags address
+prt_str_flag    .equ    $0002
 
 main    .org   $0200   ; program load address for the simple test machine
         ldx    #0
@@ -22,11 +23,12 @@ loop    lda    text,x
         sta strout,x          
 
         ; Set flag to do the print
-        ldx #1           ; 0xA2, 0x01,  
-        stx print_flag   ; 0x86, 0x9E, ; Print string flag is at 0x9E
+        lda con_flags
+        ora #prt_str_flag 
+        sta con_flags   ; 0x86, 0x9A, ; Print string flag is at 0x9A
 
         ; End the program
         rts            ; 0x60 
 
         ; Variables
-text    .byte  "HELLO WORLD"
+text            .byte  "HELLO WORLD"

simple_test_machine/programs/mult10.asm

@@ -3,8 +3,9 @@
 ; For testing this program was assembled with c64 (using the -R option):
 ; https://www.aartbik.com/MISC/c64.html
 
-strout          .equ   $1100   ; console output address
-print_flag      .equ   $009E   ; str print flag address
+strout          .equ    $1100   ; console output address
+con_flags       .equ    $009A   ; console flags address
+prt_str_flag    .equ    $0001   ; print string flag
 
         ; FAST MULTIPLY program from:
         ; http://6502.org/source/integers/fastx10.htm
@@ -22,8 +23,9 @@ main    LDA #7      ; load 7 into the accumulator
         STX strout+1    ; store null terminator to output addr + 1
 
         ; Set flag to do the print
-        LDX #1           ; 0xA2, 0x01,  
-        STX $9F          ; 0x86, 0x9F, ; Print byte flag is at 0x9F
+        LDA con_flags    ; load the current console flag set
+        ORA #prt_str_flag ; turn on the print string flag
+        STA con_flags    ; store the flags back in memory
 
         ; End the program
         RTS            ; 0x60 

simple_test_machine/src/machine.rs

@@ -13,10 +13,9 @@ pub const INPUT_BUF_ADDR: u16 = 0x1200;     // Input buffer
 
 pub const CONSOLE_FLAGS_ADDR: u16 = 0x009A; // Grouping all of the console flags into a single byte
 
-pub const PRINT_BYTE_FLAG: u16 = 0x009F;    // Then set one of these flags to trigger the print
-pub const PRINT_STR_FLAG: u16 = 0x009E;     //      and indicate what type is being printed.
-
-pub const READ_KB_FLAG: u16 = 0x009D;       // Set this address to 1 to request user input from the keyboard
+pub const PRINT_BYTE_FLAG: u8 = 0x01;    // Then set one of these flags to trigger the print
+pub const PRINT_STR_FLAG:  u8 = 0x02;    //      and indicate what type is being printed.
+pub const READ_KB_FLAG:    u8 = 0x04;    // Set this address to 1 to request user input from the keyboard
 
 /////////////////////////////////////////////////////////////////////
 //				BUS
@@ -84,8 +83,8 @@ impl OutputConsole
     fn clock(_cpu: &mut R6502, bus: &mut TBus )
     {
         // Check for a string to print
-        let mut value = bus.read(PRINT_STR_FLAG);
-        if value != 0
+        let mut value = bus.read(CONSOLE_FLAGS_ADDR);
+        if (value & PRINT_STR_FLAG) != 0
         {
             let mut msg: Vec<u8> = Vec::new();
             
@@ -98,17 +97,24 @@ impl OutputConsole
             }
 
             // Mark the string as empty again
-            bus.write(PRINT_STR_FLAG, 0);
+            value &= !(PRINT_STR_FLAG);
+            bus.write(CONSOLE_FLAGS_ADDR, value);
 
             println!("{}", str::from_utf8(&msg).unwrap());
         }
 
         // Check for byte to print
-        let flag = bus.read(PRINT_BYTE_FLAG);
-        if flag != 0
+        let mut flag = bus.read(CONSOLE_FLAGS_ADDR);
+        if (flag & PRINT_BYTE_FLAG)!= 0
         {
+            // read the byte
             let byte = bus.read(OUTPUT_BUF_ADDR);
-            bus.write(PRINT_BYTE_FLAG, 0);
+
+            // reset the flag
+            flag &= !(PRINT_BYTE_FLAG);
+            bus.write(CONSOLE_FLAGS_ADDR, flag);
+
+            // print the byte
             println!("{}", byte as u8);
         }