blk: first steps

dictionary.txt

@@ -207,3 +207,7 @@ CR
 LF
 SPC
 
+*** Disk ***
+
+LIST        n --            Prints the contents of the block n on screen in the
+                            form of 16 lines of 64 columns.

emul/.gitignore

@@ -4,3 +4,4 @@
 /forth/forth
 /*/*-bin.h
 /*/*.bin
+/blkfs

emul/Makefile

@@ -1,5 +1,4 @@
 TARGETS = forth/forth
-BIN2C = ../tools/bin2c
 # Those Forth source files are in a particular order
 BOOTSRCS = ./forth/conf.fs \
 	../forth/xcomp.fs \
@@ -10,11 +9,13 @@ BOOTSRCS = ./forth/conf.fs \
 	./forth/xstop.fs
 
 FORTHSRCS = core.fs cmp.fs print.fs str.fs parse.fs readln.fs fmt.fs z80a.fs \
-	link.fs
+	link.fs blk.fs
 FORTHSRC_PATHS = ${FORTHSRCS:%=../forth/%} forth/run.fs
 OBJS = emul.o libz80/libz80.o
 SLATEST = ../tools/slatest
 STRIPFC = ../tools/stripfc
+BIN2C = ../tools/bin2c
+BLKPACK = ../tools/blkpack
 
 .PHONY: all
 all: $(TARGETS)
@@ -22,6 +23,7 @@ all: $(TARGETS)
 $(STRIPFC):
 $(SLATEST):
 $(BIN2C):
+$(BLKPACK):
 	$(MAKE) -C ../tools
 
 # z80c.bin is not in the prerequisites because it's a bootstrap
@@ -55,7 +57,10 @@ forth/forth1-bin.h: forth/forth1.bin $(BIN2C)
 forth/stage2: forth/stage.c $(OBJS) forth/forth1-bin.h 
 	$(CC) -DSTAGE2 forth/stage.c $(OBJS) -o $@
 
-forth/forth: forth/forth.c $(OBJS) forth/forth1-bin.h 
+blkfs: $(BLKPACK)
+	$(BLKPACK) ../blk > $@
+
+forth/forth: forth/forth.c $(OBJS) forth/forth1-bin.h blkfs
 	$(CC) forth/forth.c $(OBJS) -o $@
 
 libz80/libz80.o: libz80/z80.c

emul/forth/forth.c

@@ -11,10 +11,15 @@
 // This binary is also used for automated tests and those tests, when
 // failing, send a non-zero value to RET_PORT to indicate failure
 #define RET_PORT 0x01
+// Port for block reads. Write 2 bytes, MSB first, on that port and then
+// read 1024 bytes from the same port.
+#define BLK_PORT 0x03
 
 static int running;
 static FILE *fp;
+static FILE *blkfp;
 static int retcode = 0;
+static uint16_t blkid = 0;
 
 static uint8_t iord_stdio()
 {
@@ -39,6 +44,27 @@ static void iowr_ret(uint8_t val)
     retcode = val;
 }
 
+static uint8_t iord_blk()
+{
+    uint8_t res = 0;
+    if (blkfp != NULL) {
+        int c = getc(blkfp);
+        if (c != EOF) {
+            res = c;
+        }
+    }
+    return res;
+}
+
+static void iowr_blk(uint8_t val)
+{
+    blkid <<= 8;
+    blkid |= val;
+    if (blkfp != NULL) {
+        fseek(blkfp, blkid*1024, SEEK_SET);
+    }
+}
+
 
 int main(int argc, char *argv[])
 {
@@ -67,11 +93,14 @@ int main(int argc, char *argv[])
         fprintf(stderr, "Usage: ./forth [filename]\n");
         return 1;
     }
+    blkfp = fopen("blkfs", "r+");
     Machine *m = emul_init();
     m->ramstart = RAMSTART;
     m->iord[STDIO_PORT] = iord_stdio;
     m->iowr[STDIO_PORT] = iowr_stdio;
     m->iowr[RET_PORT] = iowr_ret;
+    m->iord[BLK_PORT] = iord_blk;
+    m->iowr[BLK_PORT] = iowr_blk;
     // initialize memory
     for (int i=0; i<sizeof(KERNEL); i++) {
         m->mem[i] = KERNEL[i];
@@ -89,6 +118,7 @@ int main(int argc, char *argv[])
         tcsetattr(0, TCSAFLUSH, &termInfo);
         emul_printdebug();
     }
+    fclose(blkfp);
     fclose(fp);
     return retcode;
 }

emul/forth/run.fs

@@ -1 +1,15 @@
-: INIT CURRENT @ HERE ! RDLN$ Z80A$ INTERPRET ;
+: EFS@
+    256 /MOD 3 PC! 3 PC!
+    1024 0 DO
+        3 PC@
+        BLK( I + C!
+    LOOP
+;
+: INIT
+    CURRENT @ HERE !
+    BLK$
+    ['] EFS@ BLK@* !
+    RDLN$
+    Z80A$
+    INTERPRET
+;

forth/blk.fs

@@ -0,0 +1,32 @@
+( I/O blocks )
+
+: BLKMEM+ 0x57 RAM+ @ + ;
+( n -- Fetches block n and write it to BLK( )
+: BLK@* 0 BLKMEM+ ;
+( n -- Write back BLK( to storage at block n )
+: BLK!* 2 BLKMEM+ ;
+( Current blk pointer in ( )
+: BLK> 4 BLKMEM+ ;
+: BLK( 6 BLKMEM+ ;
+
+: BLK$
+    H@ 0x57 RAM+ !
+    1030 ALLOT
+    -1 BLK> !
+;
+
+: BLK@
+    DUP BLK> = IF DROP EXIT THEN
+    DUP BLK> ! BLK@* @ EXECUTE
+;
+
+: .2 DUP 10 < IF SPC THEN . ;
+
+: LIST
+    BLK@
+    16 0 DO
+        I 1 + .2 SPC
+        64 I * BLK( + (print)
+        CRLF
+    LOOP
+;

forth/fmt.fs

@@ -62,7 +62,7 @@
         EMIT
         1 +
     LOOP
-    LF
+    CRLF
 ;
 
 ( n a -- )

forth/print.fs

@@ -32,4 +32,5 @@
 : BS 8 EMIT ;
 : LF 10 EMIT ;
 : CR 13 EMIT ;
+: CRLF CR LF ;
 : SPC 32 EMIT ;

notes.txt

@@ -71,7 +71,7 @@ other fields, the only one they have is the "flags" field.
 There are some core variables in the core system that are referred to directly
 by their address in memory throughout the code. The place where they live is
 configurable by the RAMSTART constant in conf.fs, but their relative offset is
-not. In fact, they're mostlly referred to directly as their numerical offset
+not. In fact, they're mostly referred to directly as their numerical offset
 along with a comment indicating what this offset refers to.
 
 This system is a bit fragile because every time we change those offsets, we
@@ -91,7 +91,7 @@ RAMSTART   INITIAL_SP
 +51        CURRENTPTR
 +53        readln's variables
 +55        adev's variables
-+57        FUTURE USES
++57        blk's variables
 +59        z80a's variables
 +5b        FUTURE USES
 +70        DRIVERS