Start on FILE i/O

CMakelists.txt

@@ -23,12 +23,13 @@ target_compile_options(${CMAKE_PROJECT_NAME} PRIVATE
 )
 
 target_sources(${CMAKE_PROJECT_NAME} PRIVATE
-  "src/main.c"
+  src/main.c
-  "src/ram.c"
+  src/ram.c
   src/cpu.c
   src/rom.c
-  src/io.c
+  src/memory.c
-  src/memoryMap.c
+  src/file.c
+  src/screen.c
 )
 
 target_include_directories(${CMAKE_PROJECT_NAME} PRIVATE

inc/file.h

@@ -0,0 +1,17 @@
+#ifndef FILE_H
+#define FILE_H
+
+#define COMMAND_OPEN 1
+#define COMMAND_CLOSE 2
+#define COMMAND_SELECT_IN 3
+#define COMMAND_SELECT_OUT 4
+#define COMMAND_READ 5
+#define COMMAND_WRITE 6
+#define COMMAND_RESET 7
+
+int openFile(int fd, const char *path);
+int closeFile(int fd);
+int readByte(const int fd, int *data);
+int writeByte(const int fd, const int data);
+
+#endif // FILE_H

inc/io.h

@@ -9,8 +9,9 @@
 #define SCREEN_ADDRESS 0
 #define KEYBOARD_ADDRESS 1
 #define ROM_BANKED_OUT 2
-
+#define FILE_COMMAND 3
-int putChar(uint8_t c);
+#define FILE_DESCRIPTOR 4
-int getChar(void);
+#define FILE_DATA 5 // two bytes, for pointer to string
+#define FILE_STATUS 7
 
 #endif // IO_H

inc/memory.h

@@ -1,11 +1,13 @@
-#ifndef MEMORY_MAP_H
+#ifndef MEMORY_H
-#define MEMORY_MAP_H
+#define MEMORY_H
 
 #include <stdint.h>
 
+#include "file.h"
 #include "io.h"
 #include "ram.h"
 #include "rom.h"
+#include "screen.h"
 
 uint8_t readMemory(uint16_t address, uint8_t *ram, uint8_t *rom);
 void writeMemory(uint16_t address, uint8_t value, uint8_t *ram);
@@ -13,4 +15,4 @@ void writeMemory(uint16_t address, uint8_t value, uint8_t *ram);
 uint8_t readStack(uint8_t address, uint8_t *ram);
 void writeStack(uint8_t address, uint8_t value, uint8_t *ram);
 
-#endif // MEMORY_MAP_H
+#endif // MEMORY_H

inc/screen.h

@@ -0,0 +1,9 @@
+#ifndef SCREEN_H
+#define SCREEN_H
+
+#include <stdint.h>
+
+int putChar(uint8_t c);
+int getChar(void);
+
+#endif // SCREEN_H

rom/defines.s

@@ -5,6 +5,29 @@ WIDTH                         := 80 ; Default terminal width
 WIDTH2                := 70 ; mac column for zoned print
 RAMSTART2             := $0400
 
+; io registers
+IO_SCREEN             := $BC00
+IO_KBD                := $BC01
+IO_ROM_BANKED_OUT     := $BC02
+IO_FILE_COMMAND       := $BC03
+IO_FILE_DESCRIPTOR    := $BC04
+IO_FILE_DATA          := $BC05
+IO_FILE_STATUS        := $BC07
+
+; io commands
+IO_COMMAND_OPEN       := 1
+IO_COMMAND_CLOSE      := 2
+IO_COMMAND_SELECT_IN  := 3
+IO_COMMAND_SELECT_OUT := 4
+IO_COMMAND_READ       := 5
+IO_COMMAND_WRITE      := 6
+IO_COMMAND_RESET      := 7
+
+; io status
+FILE_STATUS_ERROR     := $01
+FILE_STATUS_EOF       := $02
+FILE_STATUS_READY     := $04
+
 BYTES_FP              := 5
 BYTES_PER_ELEMENT     := BYTES_FP
 BYTES_PER_VARIABLE    := BYTES_FP+2

rom/error.s

@@ -14,9 +14,7 @@ define_error ERR_ZERODIV, "DIVISION BY ZERO"
 define_error ERR_ILLDIR, "ILLEGAL DIRECT"
 define_error ERR_BADTYPE, "TYPE MISMATCH"
 define_error ERR_STRLONG, "STRING TOO LONG"
-.ifdef CONFIG_FILE
 define_error ERR_BADDATA, "FILE DATA"
-.endif
 define_error ERR_FRMCPX, "FORMULA TOO COMPLEX"
 define_error ERR_CANTCONT, "CAN'T CONTINUE"
 define_error ERR_UNDEFFN, "UNDEF'D FUNCTION"

rom/extra.s

@@ -1,29 +1,121 @@
 .segment "EXTRA"
 
-LOAD:
+; IO
+
+CHKIN:
+        stx CURDVC
+        stx IO_FILE_DESCRIPTOR
+        lda IO_COMMAND_SELECT_IN
+        sta IO_FILE_COMMAND
         rts
 
-SAVE:
+CHKOUT:
+        stx CURDVC
+        stx IO_FILE_DESCRIPTOR
+        lda IO_COMMAND_SELECT_OUT
+        sta IO_FILE_COMMAND
         rts
 
+CLRCH:
+        lda #0
+        sta CURDVC
+        lda IO_COMMAND_RESET
+        sta IO_FILE_COMMAND
+        rts
+
+CHRIN:
+        lda CURDVC
+        bne @file
+        lda IO_KBD
+        bmi @end
+        jsr CHROUT ; echo
+@file:
+        lda IO_COMMAND_READ
+        sta IO_FILE_COMMAND
+@wait:
+        lda IO_FILE_STATUS
+        and #FILE_STATUS_READY
+        beq @wait
+        lda IO_FILE_DATA
+@end:
+        rts
+
+CHROUT:
+        lda CURDVC
+        bne @file
+        sta IO_SCREEN
+        rts
+@file:
+        sta IO_FILE_DATA
+        lda IO_COMMAND_WRITE
+        sta IO_FILE_COMMAND
+@wait:
+        lda IO_FILE_STATUS
+        and #$4
+        beq @wait
+        rts
+
+OPEN:
+        jsr GETBYT
+        stx IO_FILE_DESCRIPTOR
+        jsr CHKCOM
+        jsr FRMEVL
+        jsr CHKSTR
+        jsr FREFAC
+        sta STRNG2
+        ldy #0
+@copy:
+        cpy STRNG2
+        beq @done_copy
+        lda (INDEX),y
+        sta FILE_NAME_BUFFER,y
+        iny
+        bne @copy
+@done_copy:
+        lda #0
+        sta FILE_NAME_BUFFER,y
+        lda #<FILE_NAME_BUFFER
+        sta IO_FILE_DATA
+        lda #>FILE_NAME_BUFFER
+        sta IO_FILE_DATA+1
+        lda #IO_COMMAND_OPEN
+        sta IO_FILE_COMMAND
+@wait:
+        lda IO_FILE_STATUS
+        and #FILE_STATUS_READY
+        beq @wait
+        lda #FILE_STATUS_READY
+        and #$01
+        bne @error
+        rts
+@error:
+        jmp     IQERR
+
+CLOSE:
+        rts
+
+; Default
+
 ISCNTC:
-        lda $BC01
+        lda IO_KBD
         cmp #$03
         beq :+
         rts
 :
         jmp STOP
 
-MONRDKEY:
+SYS:
-        lda $BC01
+        jsr GTNUM
-        bmi :+
+        lda LINNUM
-        sta $BC00       ; echo
+        sta SYSJMP+1
-:
+        lda LINNUM+1
+        sta SYSJMP+2
+SYSJMP:
+        jsr $FFFF
         rts
 
-MONCOUT:
+MONRDKEY := CHRIN
-        sta $BC00
+MONCOUT  := CHROUT
-        rts
 
 .segment "WOZMON"
 .include "wozmon.s"

rom/init.s

@@ -77,9 +77,9 @@ L4098:
       sta     INPUTBUFFER-4
       ldx     #TEMPST
       stx     TEMPPT
-      lda     #<$BC00     ; Start of IO
+      lda     #<IO_SCREEN     ; Start of IO
       sta     MEMSIZ
-      lda     #>$BC00
+      lda     #>IO_SCREEN
       sta     MEMSIZ+1
       sta     FRETOP
       sty     FRETOP+1

rom/inline.s

@@ -40,13 +40,9 @@ L2453:
         jmp     L29B9
 
 GETLN:
-    .ifdef CONFIG_FILE
         jsr     CHRIN
         ldy     CURDVC
         bne     L2465
-    .else
-        jsr     MONRDKEY
-    .endif
         cmp     #$0F
         bne     L2465
         pha

rom/input.s

@@ -22,13 +22,11 @@ L2A67:
 SYNERR4:
         jmp     SYNERR
 RESPERR:
-.ifdef CONFIG_FILE
         lda     CURDVC
         beq     LCA8F
         ldx     #ERR_BADDATA
         jmp     ERROR
 LCA8F:
-.endif
         lda     #<ERRREENTRY
         ldy     #>ERRREENTRY
         jsr     STROUT
@@ -45,7 +43,6 @@ RTS20:
 GET:
         jsr     ERRDIR
 ; CBM: if GET#, then switch input
-.ifdef CONFIG_FILE
         cmp     #'#'
         bne     LCAB6
         jsr     CHRGET
@@ -55,7 +52,6 @@ GET:
         jsr     CHKIN
         stx     CURDVC
 LCAB6:
-.endif
         ldx     #<(INPUTBUFFER+1)
         ldy     #>(INPUTBUFFER+1)
         lda     #$00
@@ -63,16 +59,13 @@ LCAB6:
         lda     #$40
         jsr     PROCESS_INPUT_LIST
 ; CBM: if GET#, then switch input back
-.ifdef CONFIG_FILE
         ldx     CURDVC
         bne     LCAD8
-.endif
         rts
 
 ; ----------------------------------------------------------------------------
 ; "INPUT#" STATEMENT
 ; ----------------------------------------------------------------------------
-.ifdef CONFIG_FILE
 INPUTH:
         jsr     GETBYT
         lda     #$2C
@@ -88,7 +81,6 @@ LCAD8:
         stx     CURDVC
         rts
 LCAE0:
-.endif
 
 ; ----------------------------------------------------------------------------
 ; "INPUT" STATEMENT
@@ -107,30 +99,24 @@ L2A9E:
         sta     INPUTBUFFER-1
 LCAF8:
         jsr     NXIN
-  .ifdef CONFIG_FILE
         lda     CURDVC
         beq     LCB0C
-        lda     Z96
+        lda     IO_FILE_STATUS
-        and     #$02
+        and     #FILE_STATUS_EOF
         beq     LCB0C
         jsr     LCAD6
         jmp     DATA
 LCB0C:
-  .endif
         lda     INPUTBUFFER
         bne     L2ABE
-  .ifdef CONFIG_FILE
         lda     CURDVC
         bne     LCAF8
-  .endif
         clc
         jmp     CONTROL_C_TYPED
 
 NXIN:
-  .ifdef CONFIG_FILE
         lda     CURDVC
         bne     LCB21
-  .endif
         jsr     OUTQUES	; '?'
         jsr     OUTSP
 LCB21:
@@ -196,10 +182,8 @@ PROCESS_INPUT_ITEM:
         bne     L2AF8	; always
 L2AF0:
         bmi     FINDATA
-.ifdef CONFIG_FILE
         lda     CURDVC
         bne     LCB64
-.endif
         jsr     OUTQUES
 LCB64:
         jsr     NXIN
@@ -300,10 +284,8 @@ L2B94:
         ldy     #$00
         lda     (INPTR),y
         beq     L2BA1
-.ifdef CONFIG_FILE
         lda     CURDVC
         bne     L2BA1
-.endif
         lda     #<ERREXTRA
         ldy     #>ERREXTRA
         jmp     STROUT

rom/misc1.s

@@ -142,7 +142,6 @@ L2963:
 RET5:
         rts
 
-.ifdef CONFIG_FILE
 PRINTH:
         jsr     CMD
         jmp     LCAD6
@@ -157,5 +156,3 @@ LC98F:
         stx     CURDVC
         plp
         jmp     PRINT
-.endif
-

rom/print.s

@@ -43,10 +43,8 @@ L29B9:
         sta     INPUTBUFFER,x
         ldx     #<(INPUTBUFFER-1)
         ldy     #>(INPUTBUFFER-1)
-  .ifdef CONFIG_FILE
         lda     CURDVC
         bne     L29DD
-  .endif
 
 CRDO:
         lda     #CR
@@ -124,7 +122,6 @@ L2A22:
         jmp     L2A22
 ; ----------------------------------------------------------------------------
 OUTSP:
-.ifdef CONFIG_FILE
 ; on non-screen devices, print SPACE
 ; instead of CRSR RIGHT
         lda     CURDVC
@@ -133,9 +130,6 @@ OUTSP:
         .byte   $2C
 LCA40:
         lda     #$1D ; CRSR RIGHT
-.else
-        lda     #$20
-.endif
         .byte   $2C
 OUTQUES:
         lda     #$3F

rom/program.s

@@ -20,14 +20,12 @@ MEMERR:
 ; ----------------------------------------------------------------------------
 ERROR:
         lsr     Z14
-.ifdef CONFIG_FILE
         lda     CURDVC    ; output
         beq     LC366     ; is screen
         jsr     CLRCH     ; otherwise redirect output back to screen
         lda     #$00
         sta     CURDVC
 LC366:
-.endif
         jsr     CRDO
         jsr     OUTQUES
 L2329:

rom/token.s

@@ -6,9 +6,7 @@
         keyword_rts "FOR", FOR
         keyword_rts "NEXT", NEXT
         keyword_rts "DATA", DATA
-.ifdef CONFIG_FILE
         keyword_rts "INPUT#", INPUTH
-.endif
         keyword_rts "INPUT", INPUT
         keyword_rts "DIM", DIM
         keyword_rts "READ", READ
@@ -25,19 +23,15 @@
         keyword_rts "WAIT", WAIT
         keyword_rts "DEF", DEF
         keyword_rts "POKE", POKE
-.ifdef CONFIG_FILE
         keyword_rts "PRINT#", PRINTH
-.endif
         keyword_rts "PRINT", PRINT, TOKEN_PRINT
         keyword_rts "CONT", CONT
         keyword_rts "LIST", LIST
         keyword_rts "CLEAR", CLEAR
-.ifdef CONFIG_FILE
         keyword_rts "CMD", CMD
         keyword_rts "SYS", SYS
         keyword_rts "OPEN", OPEN
         keyword_rts "CLOSE", CLOSE
-.endif
         keyword_rts "GET", GET
         keyword_rts "NEW", NEW
 

rom/wozmon.s

@@ -33,7 +33,7 @@ BACKSPACE:      DEY                    ; Back up text index.
                 BMI     GETLINE        ; Beyond start of line, reinitialize.
 
 NEXTCHAR:
-                LDA     $BC01          ; Check status.
+                LDA     IO_KBD         ; Check status.
                 BMI     NEXTCHAR       ; Loop until ready.
                 STA     IN,Y           ; Add to text buffer.
                 JSR     ECHO           ; Display character.
@@ -165,5 +165,5 @@ PRHEX:
                 ADC     #$06           ; Add offset for letter.
 
 ECHO:
-                STA     $BC00          ; Output character.
+                STA     IO_SCREEN      ; Output character.
                 RTS                    ; Return.

rom/zeropage.s

@@ -28,7 +28,6 @@ TXPSV:
 INPUTBUFFER = $0200
 
 .org $12
-
 CHARAC:
 	.res 1
 ENDCHR:
@@ -51,7 +50,6 @@ Z14:
 	.res 1
 
 .org $1D
-
 TEMPPT:
 	.res 1
 LASTPT:
@@ -156,3 +154,6 @@ TXTPTR = <(GENERIC_TXTPTR-GENERIC_CHRGET + CHRGET)
 CHRGOT = <(GENERIC_CHRGOT-GENERIC_CHRGET + CHRGET)
 CHRGOT2 = <(GENERIC_CHRGOT2-GENERIC_CHRGET + CHRGET)
 RNDSEED = <(GENERIC_RNDSEED-GENERIC_CHRGET + CHRGET)
+CURDVC:
+	.res 1
+FILE_NAME_BUFFER = $0300

src/cpu.c

@@ -1,6 +1,6 @@
 #include "cpu.h"
 
-#include "memoryMap.h"
+#include "memory.h"
 #include "opcodes.h"
 
 #define COMBINE(H, L) ((H << 8) | L)

src/file.c

@@ -0,0 +1,63 @@
+#include "file.h"
+
+#include <errno.h>
+#include <stdio.h>
+
+// Up to 256 files can be open
+FILE *files[256];
+
+int openFile(int fd, const char *path) {
+  files[fd] = fopen(path, "r+");
+  if (files[fd] == NULL) {
+    return errno;
+  }
+
+  return 0;
+}
+
+int closeFile(int fd) {
+  int ret = fclose(files[fd]);
+  if (ret != 0) {
+    return errno;
+  }
+
+  return 0;
+}
+
+int readByte(const int fd, int *data) {
+  int status = 0;
+  int count = fread(&data, 1, 1, files[fd]);
+  // Error or EOF
+  if (count != 1) {
+    int error = ferror(files[fd]);
+    int eof = feof(files[fd]);
+    if (error != 0) {
+      status = 0x2;
+    } else if (eof != 0) {
+      status = 0x1;
+    } else {
+      status = 0x4;
+    }
+  }
+
+  return status;
+}
+
+int writeByte(const int fd, const int data) {
+  int status = 0;
+  int count = fwrite(&data, 1, 1, files[fd]);
+  // Error or EOF
+  if (count != 1) {
+    int error = ferror(files[fd]);
+    int eof = feof(files[fd]);
+    if (error != 0) {
+      status = 0x2;
+    } else if (eof != 0) {
+      status = 0x1;
+    } else {
+      status = 0x4;
+    }
+  }
+
+  return status;
+}

src/main.c

@@ -46,7 +46,7 @@ int main(void) {
 
   printf("6502PC Emulator with MS Basic\n");
   printf("CTRL + G to exit\n");
-  printf("WOZMON available, BASIC at DF6A\n");
+  printf("WOZMON available, BASIC at E032\n");
 
   clock_gettime(CLOCK_MONOTONIC, &emulationStart);
 

src/memory.c

@@ -1,4 +1,4 @@
-#include "memoryMap.h"
+#include "memory.h"
 
 uint8_t readMemory(uint16_t address, uint8_t *ram, uint8_t *rom) {
   // RAM/ROM
@@ -16,10 +16,18 @@ uint8_t readMemory(uint16_t address, uint8_t *ram, uint8_t *rom) {
       case KEYBOARD_ADDRESS: {
         return getChar();
       }
+
       case ROM_BANKED_OUT: {
         return ram[IO_BASE + ROM_BANKED_OUT];
       }
 
+      case FILE_DATA: {
+        return ram[IO_BASE + FILE_DATA];
+      }
+      case FILE_STATUS: {
+        return ram[IO_BASE + FILE_STATUS];
+      }
+
       default:
         break;
     }
@@ -55,6 +63,33 @@ void writeMemory(uint16_t address, uint8_t value, uint8_t *ram) {
       ram[IO_BASE + ROM_BANKED_OUT] = value;
       break;
 
+    case FILE_COMMAND: {
+      switch (ram[IO_BASE + FILE_COMMAND]) {
+        case COMMAND_OPEN: {
+          ram[IO_BASE + FILE_STATUS] = 0;
+          ram[IO_BASE + FILE_STATUS] = openFile(ram[IO_BASE + FILE_DESCRIPTOR], (const char *)&ram[IO_BASE + FILE_DATA]);
+          break;
+        }
+        case COMMAND_CLOSE: {
+          ram[IO_BASE + FILE_STATUS] = 0;
+          ram[IO_BASE + FILE_STATUS] = closeFile(ram[IO_BASE + FILE_DESCRIPTOR]);
+          break;
+        }
+
+        default:
+          break;
+      }
+      break;
+    }
+    case FILE_DESCRIPTOR: {
+      ram[IO_BASE + FILE_DESCRIPTOR] = value;
+      break;
+    }
+    case FILE_DATA: {
+      ram[IO_BASE + FILE_DATA] = value;
+      break;
+    }
+
     default:
       break;
   }

src/screen.c

@@ -1,4 +1,4 @@
-#include "io.h"
+#include "screen.h"
 
 #include <stdio.h>
 #include <stdlib.h>