pcat: implement AT-XY

VE works! well, at this point, we can say that Collapse OS runs on
PC/AT. A little cleanup and docs writing and we're done!

emul/emul.c

@@ -5,10 +5,13 @@ They all run on the same kind of virtual machine: A z80 CPU, 64K of RAM/ROM.
 
 #include <string.h>
 #include "emul.h"
-// Port for block reads. Write 2 bytes, MSB first, on that port and then
-// read 1024 bytes from the DATA port.
+// Port for block reads. Each read or write has to be done in 5 IO writes:
+// 1 - r/w. 1 for read, 2 for write.
+// 2 - blkid MSB
+// 3 - blkid LSB
+// 4 - dest addr MSB
+// 5 - dest addr LSB
 #define BLK_PORT 0x03
-#define BLKDATA_PORT 0x04
 
 #ifndef BLKFS_PATH
 #error BLKFS_PATH needed
@@ -19,7 +22,7 @@ They all run on the same kind of virtual machine: A z80 CPU, 64K of RAM/ROM.
 
 static Machine m;
 static ushort traceval = 0;
-static uint16_t blkid = 0;
+static uint64_t blkop = 0; // 5 bytes
 static FILE *blkfp;
 
 static uint8_t io_read(int unused, uint16_t addr)
@@ -47,19 +50,20 @@ static void io_write(int unused, uint16_t addr, uint8_t val)
 
 static void iowr_blk(uint8_t val)
 {
-    blkid <<= 8;
-    blkid |= val;
-    fseek(blkfp, blkid*1024, SEEK_SET);
-}
-
-static uint8_t iord_blkdata()
-{
-    return getc(blkfp);
-}
-
-static void iowr_blkdata(uint8_t val)
-{
-    putc(val, blkfp);
+    blkop <<= 8;
+    blkop |= val;
+    uint8_t rw = blkop >> 32;
+    if (rw) {
+        uint16_t blkid = (blkop >> 16);
+        uint16_t dest = blkop & 0xffff;
+        blkop = 0;
+        fseek(blkfp, blkid*1024, SEEK_SET);
+        if (rw==2) { // write
+            fwrite(&m.mem[dest], 1024, 1, blkfp);
+        } else { // read
+            fread(&m.mem[dest], 1024, 1, blkfp);
+        }
+    }
 }
 
 static uint8_t mem_read(int unused, uint16_t addr)
@@ -120,8 +124,6 @@ Machine* emul_init()
     m.cpu.ioRead = io_read;
     m.cpu.ioWrite = io_write;
     m.iowr[BLK_PORT] = iowr_blk;
-    m.iord[BLKDATA_PORT] = iord_blkdata;
-    m.iowr[BLKDATA_PORT] = iowr_blkdata;
     return &m;
 }
 

emul/forth.c

@@ -13,10 +13,6 @@
 // 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 DATA port.
-#define BLK_PORT 0x03
-#define BLKDATA_PORT 0x04
 #define SETX_PORT 0x05
 #define SETY_PORT 0x06
 

emul/xcomp.fs

@@ -10,17 +10,14 @@
 : (emit) 0 PC! ;
 : (key) 0 PC@ ;
 : EFS@
-    256 /MOD 3 PC! 3 PC!
-    1024 0 DO
-        4 PC@
-        BLK( I + C!
-    LOOP
+    1 3 PC! ( read )
+    256 /MOD 3 PC! 3 PC! ( blkid )
+    BLK( 256 /MOD 3 PC! 3 PC! ( dest )
 ;
 : EFS!
-    256 /MOD 3 PC! 3 PC!
-    1024 0 DO
-        BLK( I + C@ 4 PC!
-    LOOP
+    2 3 PC! ( write )
+    256 /MOD 3 PC! 3 PC! ( blkid )
+    BLK( 256 /MOD 3 PC! 3 PC! ( dest )
 ;
 : COLS 80 ; : LINES 32 ;
 : AT-XY 6 PC! ( y ) 5 PC! ( x ) ;

recipes/pcat/xcomp.fs

@@ -12,10 +12,11 @@ CODE (emit) 1 chkPS,
 CODE (key)
     AH AH XORrr, 0x16 INT, AH AH XORrr, AX PUSHx,
 ;CODE
-CODE 13H08H ( driveno -- cx )
+CODE 13H08H ( driveno -- cx dx )
     DI POPx, DX PUSHx, ( protect ) DX DI MOVxx, AX 0x800 MOVxI,
     DI DI XORxx, ES DI MOVsx,
-    0x13 INT, DX POPx, ( unprotect ) CX PUSHx,
+    0x13 INT, DI DX MOVxx, DX POPx, ( unprotect )
+    CX PUSHx, DI PUSHx,
     DI 0x800 MOVxI, ES DI MOVsx,
 ;CODE
 CODE 13H ( ax bx cx dx -- ax bx cx dx )
@@ -25,24 +26,37 @@ CODE 13H ( ax bx cx dx -- ax bx cx dx )
     AX PUSHx, BX PUSHx, CX PUSHx, SI PUSHx,
 ;CODE
 : FDSPT 0x70 RAM+ ;
-: _ ( dest secno )
+: FDHEADS 0x71 RAM+ ;
+: _ ( AX BX sec )
     ( AH=read sectors, AL=1 sector, BX=dest,
       CH=trackno CL=secno DH=head DL=drive )
-    0x0201 ROT ROT ( AX BX sec )
-    FDSPT @ /MOD ( AX BX sec trk )
-    2 /MOD ( AX BX sec head trk )
+    FDSPT C@ /MOD ( AX BX sec trk )
+    FDHEADS C@ /MOD ( AX BX sec head trk )
     8 LSHIFT ROT OR 1+ ( AX BX head CX )
     SWAP 8 LSHIFT 0x03 C@ ( boot drive ) OR ( AX BX CX DX )
     13H 2DROP 2DROP
 ;
 : FD@
     2 * 16 + ( blkfs starts at sector 16 )
-    BLK( OVER _ BLK( 0x200 + SWAP 1+ _ ;
-: FD! DROP ;
+    0x0201 BLK( 2 PICK _
+    0x0201 BLK( 0x200 + ROT 1+ _ ;
+: FD!
+    2 * 16 + ( blkfs starts at sector 16 )
+    0x0301 BLK( 2 PICK _
+    0x0301 BLK( 0x200 + ROT 1+ _ ;
 : FD$
     ( get number of sectors per track with command 08H. )
-    0x03 ( boot drive ) C@ 13H08H 0x3f AND FDSPT !
+    0x03 ( boot drive ) C@ 13H08H
+    8 RSHIFT 1+ FDHEADS C!
+    0x3f AND FDSPT C!
 ;
+: COLS 80 ; : LINES 25 ;
+CODE AT-XY ( x y )
+    ( DH=row DL=col BH=page )
+    AX POPx, BX POPx, DX PUSHx, ( protect )
+    DH AL MOVrr, DL BL MOVrr, BX BX XORxx, AH 2 MOVri,
+    0x10 INT, DX POPx, ( unprotect )
+;CODE
 380 LOAD  ( xcomp core high )
 (entry) _
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