sms: add support for VDP's text mode

Because that mode behaves exactly like in a regular TMS9918, a new
driver for TMS9918 has been added in blkfs and SMS' VDP now uses it.

Also, fix broken 5x7 font.

arch/z80/sms/blk/602

@@ -1,16 +1,11 @@
-VDP Driver
+( VDP Driver. requires TMS9918 driver. Load range B602-B604. )
-
+CREATE _idat
-Implement (emit) on the console. Characters start at the top
+0b00000100 C, 0x80 C, ( Bit 2: Select mode 4 )
-left. Every (emit) call converts the ASCII char received to its
+0b00000000 C, 0x81 C,
-internal font, then put that char on screen, advancing the
+0b00001111 C, 0x82 C, ( Name table: 0x3800, *B0 must be 1* )
-cursor by one. When reaching the end of the line (33rd char),
+0b11111111 C, 0x85 C, ( Sprite table: 0x3f00 )
-wrap to the next.
+0b11111111 C, 0x86 C, ( sprite use tiles from 0x2000 )
-
+0b11111111 C, 0x87 C, ( Border uses palette 0xf )
-In the future, there's going to be a scrolling mechanism when
+0b00000000 C, 0x88 C, ( BG X scroll )
-we reach the bottom of the screen, but for now, when the end of
+0b00000000 C, 0x89 C, ( BG Y scroll )
-the screen is reached, we wrap up to the top.
+0b11111111 C, 0x8a C, ( Line counter (why have this?) )
-
-When reaching a new line, we clear that line and the next to
-help readability.
-
-Load range: 623-628

arch/z80/sms/blk/603

@@ -1,9 +1,14 @@
-CODE _ctl ( a -- sends LSB then MSB )
+: _zero ( x -- send 0 _data x times )
-    HL POP, chkPS,
+    ( x ) 0 DO 0 _data LOOP ;
-    A L LDrr, VDP_CTLPORT OUTiA,
+( Each row in ~FNT is a row of the glyph and there is 7 of
-    A H LDrr, VDP_CTLPORT OUTiA,
+them.  We insert a blank one at the end of those 7. For each
-;CODE
+row we set, we need to send 3 zero-bytes because each pixel in
-CODE _data
+the tile is actually 4 bits because it can select among 16
-    HL POP, chkPS,
+palettes. We use only 2 of them, which is why those bytes
-    A L LDrr, VDP_DATAPORT OUTiA,
+always stay zero. )
-;CODE
+: _sfont ( a -- Send font to VDP )
+    7 0 DO C@+ _data 3 _zero LOOP DROP
+    ( blank row ) 4 _zero ;
+: CELL! ( tilenum pos )
+    2 * 0x7800 OR _ctl ( tilenum )
+    0x5e MOD _data 1 _zero ;

arch/z80/sms/blk/604

@@ -1,9 +1,11 @@
-CODE _blank ( this is way too slow in Forth )
+: VDP$
-    A XORr, VDP_CTLPORT OUTiA,
+    9 0 DO _idat I 2 * + @ _ctl LOOP _blank
-    A 0x40 LDri, VDP_CTLPORT OUTiA,
+    ( palettes )
-    HL 0x4000 LDdi,
+    0xc000 _ctl
-    BEGIN,
+    ( BG ) 1 _zero 0x3f _data 14 _zero
-        A XORr, VDP_DATAPORT OUTiA,
+    ( sprite, inverted colors ) 0x3f _data 15 _zero
-        HL DECd, HLZ,
+    0x4000 _ctl 0x5e 0 DO ~FNT I 7 * + _sfont LOOP
-    JRNZ, AGAIN,
+    ( bit 6, enable display, bit 7, ?? ) 0x81c0 _ctl ;
-;CODE
+
+: COLS 32 ;
+: LINES 24 ;

arch/z80/sms/blk/605

@@ -1,10 +0,0 @@
-CREATE _idat
-0b00000100 C, 0x80 C, ( Bit 2: Select mode 4 )
-0b00000000 C, 0x81 C,
-0b00001111 C, 0x82 C, ( Name table: 0x3800, *B0 must be 1* )
-0b11111111 C, 0x85 C, ( Sprite table: 0x3f00 )
-0b11111111 C, 0x86 C, ( sprite use tiles from 0x2000 )
-0b11111111 C, 0x87 C, ( Border uses palette 0xf )
-0b00000000 C, 0x88 C, ( BG X scroll )
-0b00000000 C, 0x89 C, ( BG Y scroll )
-0b11111111 C, 0x8a C, ( Line counter (why have this?) )

arch/z80/sms/blk/606

@@ -1,12 +0,0 @@
-: _zero ( x -- send 0 _data x times )
-    ( x ) 0 DO 0 _data LOOP ;
-
-( Each row in ~FNT is a row of the glyph and there is 7 of
-them.  We insert a blank one at the end of those 7. For each
-row we set, we need to send 3 zero-bytes because each pixel in
-the tile is actually 4 bits because it can select among 16
-palettes. We use only 2 of them, which is why those bytes
-always stay zero. )
-: _sfont ( a -- Send font to VDP )
-    7 0 DO C@+ _data 3 _zero LOOP DROP
-    ( blank row ) 4 _zero ;

arch/z80/sms/blk/607

@@ -1,3 +0,0 @@
-: CELL! ( tilenum pos )
-    2 * 0x7800 OR _ctl ( tilenum )
-    0x5e MOD _data 1 _zero ;

arch/z80/sms/blk/608

@@ -1,11 +0,0 @@
-: VDP$
-    9 0 DO _idat I 2 * + @ _ctl LOOP _blank
-    ( palettes )
-    0xc000 _ctl
-    ( BG ) 1 _zero 0x3f _data 14 _zero
-    ( sprite, inverted colors ) 0x3f _data 15 _zero
-    0x4000 _ctl 0x5e 0 DO ~FNT I 7 * + _sfont LOOP
-    ( bit 6, enable display, bit 7, ?? ) 0x81c0 _ctl ;
-
-: COLS 32 ;
-: LINES 24 ;

arch/z80/sms/xcomp.fs

@@ -4,8 +4,8 @@
 0xddca CONSTANT PS_ADDR
 RS_ADDR 0x80 - CONSTANT SYSVARS
 0xc000 CONSTANT HERESTART
-0xbf   CONSTANT VDP_CTLPORT
+0xbf   CONSTANT TMS_CTLPORT
-0xbe   CONSTANT VDP_DATAPORT
+0xbe   CONSTANT TMS_DATAPORT
 SYSVARS 0x70 + CONSTANT GRID_MEM
 SYSVARS 0x72 + CONSTANT CPORT_MEM
 0x3f   CONSTANT CPORT_CTL
@@ -27,7 +27,8 @@ CURRENT @ XCURRENT !
 283 335 LOADR ( boot.z80 )
 353 LOAD  ( xcomp core low )
 CREATE ~FNT CPFNT7x7
-603 608 LOADR ( VDP )
+470 472 LOADR ( TMS9918 )
+602 604 LOADR ( VDP )
 402 404 LOADR ( Grid )
 625 626 LOADR ( SMS ports )
 612 617 LOADR ( PAD )

arch/z80/sms/xcompkbd.fs

@@ -5,8 +5,8 @@
 0xddca CONSTANT PS_ADDR
 RS_ADDR 0x80 - CONSTANT SYSVARS
 0xc000 CONSTANT HERESTART
-0xbf   CONSTANT VDP_CTLPORT
+0xbf   CONSTANT TMS_CTLPORT
-0xbe   CONSTANT VDP_DATAPORT
+0xbe   CONSTANT TMS_DATAPORT
 SYSVARS 0x70 + CONSTANT GRID_MEM
 SYSVARS 0x72 + CONSTANT CPORT_MEM
 0x3f   CONSTANT CPORT_CTL
@@ -28,7 +28,8 @@ CURRENT @ XCURRENT !
 283 335 LOADR ( boot.z80 )
 353 LOAD  ( xcomp core low )
 CREATE ~FNT CPFNT7x7
-603 608 LOADR ( VDP )
+470 472 LOADR ( TMS9918 )
+602 604 LOADR ( VDP )
 402 404 LOADR ( Grid )
 625 626 LOADR ( SMS ports )
 620 LOAD ( PAD ) : (ps2kc) (ps2kcA) ; 411 414 LOADR

arch/z80/sms/xcompsdc.fs

@@ -6,8 +6,8 @@
 0xddca CONSTANT PS_ADDR
 RS_ADDR 0x80 - CONSTANT SYSVARS
 0xc000 CONSTANT HERESTART
-0xbf   CONSTANT VDP_CTLPORT
+0xbf   CONSTANT TMS_CTLPORT
-0xbe   CONSTANT VDP_DATAPORT
+0xbe   CONSTANT TMS_DATAPORT
 SYSVARS 0x70 + CONSTANT GRID_MEM
 SYSVARS 0x72 + CONSTANT CPORT_MEM
 0x3f   CONSTANT CPORT_CTL
@@ -29,7 +29,8 @@ CURRENT @ XCURRENT !
 283 335 LOADR ( boot.z80 )
 353 LOAD  ( xcomp core low )
 CREATE ~FNT CPFNT7x7
-603 608 LOADR ( VDP )
+470 472 LOADR ( TMS9918 )
+602 604 LOADR ( VDP )
 402 404 LOADR ( Grid )
 625 626 LOADR ( SMS ports )
 620 LOAD ( PAD ) : (ps2kc) (ps2kcA) ; 411 414 LOADR

arch/z80/sms/xcomptextmode.fs

@@ -0,0 +1,42 @@
+( xcomp using the Text Mode if the VDP. Only works on actual
+  SMS. The Megadrive's VDP doesn't have TMS9918 modes in it. )
+( 8K of onboard RAM )
+0xdd00 CONSTANT RS_ADDR
+( Memory register at the end of RAM. Must not overwrite )
+0xddca CONSTANT PS_ADDR
+RS_ADDR 0x80 - CONSTANT SYSVARS
+0xc000 CONSTANT HERESTART
+0xbf   CONSTANT TMS_CTLPORT
+0xbe   CONSTANT TMS_DATAPORT
+SYSVARS 0x70 + CONSTANT GRID_MEM
+SYSVARS 0x72 + CONSTANT CPORT_MEM
+0x3f   CONSTANT CPORT_CTL
+0xdc   CONSTANT CPORT_D1
+0xdd   CONSTANT CPORT_D2
+SYSVARS 0x73 + CONSTANT PS2_MEM
+5 LOAD  ( z80 assembler )
+: ZFILL, ( u ) 0 DO 0 A, LOOP ;
+262 LOAD  ( xcomp )
+523 LOAD  ( font compiler )
+282 LOAD  ( boot.z80.decl )
+270 LOAD  ( xcomp overrides )
+
+DI, 0x100 JP, 0x62 ZFILL, ( 0x66 )
+RETN, 0x98 ZFILL, ( 0x100 )
+( All set, carry on! )
+CURRENT @ XCURRENT !
+0x100 BIN( !
+283 335 LOADR ( boot.z80 )
+353 LOAD  ( xcomp core low )
+CREATE ~FNT CPFNT5x7
+470 472 LOADR ( VDP )
+402 404 LOADR ( Grid )
+625 626 LOADR ( SMS ports )
+620 LOAD ( PAD ) : (ps2kc) (ps2kcA) ; 411 414 LOADR
+390 LOAD  ( xcomp core high )
+(entry) _
+( Update LATEST )
+PC ORG @ 8 + !
+," TMS$ 0 0 AT-XY PS2$ (im1) " EOT,
+ORG @ 0x100 - 256 /MOD 2 PC! 2 PC!
+H@ 256 /MOD 2 PC! 2 PC!

blk/001

@@ -9,4 +9,5 @@ MASTER INDEX
 400 AT28 EEPROM driver        401 Grid subsystem
 410 PS/2 keyboard subsystem   418 Z80 SPI Relay driver
 420 SD Card subsystem         440 8086 boot code
-470-519 unused                520 Fonts
+470 Z80 TMS9918 driver
+480-519 unused                520 Fonts

blk/470

@@ -0,0 +1,12 @@
+( Z80 driver for TMS9918. Implements grid protocol. Requires
+TMS_CTLPORT, TMS_DATAPORT and ~FNT from the Font compiler at
+B520. Load range B470-472 )
+CODE _ctl ( a -- sends LSB then MSB )
+    HL POP, chkPS,
+    A L LDrr, TMS_CTLPORT OUTiA,
+    A H LDrr, TMS_CTLPORT OUTiA,
+;CODE
+CODE _data
+    HL POP, chkPS,
+    A L LDrr, TMS_DATAPORT OUTiA,
+;CODE

blk/471

@@ -0,0 +1,9 @@
+CODE _blank ( this is way too slow in Forth )
+    A XORr, TMS_CTLPORT OUTiA,
+    A 0x40 LDri, TMS_CTLPORT OUTiA,
+    HL 0x4000 LDdi,
+    BEGIN,
+        A XORr, TMS_DATAPORT OUTiA,
+        HL DECd, HLZ,
+    JRNZ, AGAIN,
+;CODE

blk/472

@@ -0,0 +1,16 @@
+( Each row in ~FNT is a row of the glyph and there is 7 of
+them.  We insert a blank one at the end of those 7. )
+: _sfont ( a -- Send font to TMS )
+    7 0 DO C@+ _data LOOP DROP
+    ( blank row ) 0 _data ;
+: CELL! ( tilenum pos )
+    0x7800 OR _ctl ( tilenum )
+    0x5e MOD _data ;
+: COLS 40 ; : LINES 24 ;
+: TMS$
+    0x8100 _ctl ( blank screen ) _blank
+    0x4000 _ctl 0x5e 0 DO ~FNT I 7 * + _sfont LOOP
+    0x820e _ctl ( name table 0x3800 )
+    0x8400 _ctl ( patter table 0x0000 )
+    0x87f0 _ctl ( colors 0 and 1 )
+    0x8000 _ctl 0x81d0 _ctl ( text mode, display on ) ;

blk/523

@@ -9,7 +9,7 @@
         DUP I 5 * + _g
     LOOP ;
 : CPFNT5x7
-    0 , 0 , 0 C, ( space char )
+    0 , 0 , 0 , 0 C, ( space char )
-    534 532 DO I BLK@ BLK( 12 _l 448 + 12 _l DROP LOOP ( 72 )
+    535 532 DO I BLK@ BLK( 12 _l 448 + 12 _l DROP LOOP ( 72 )
     535 BLK@ BLK( 12 _l 448 + 10 _l DROP ( 94! )
 ;

emul/z80/sms.c

@@ -34,7 +34,7 @@ static xcb_gcontext_t       fg;
 static xcb_drawable_t       win;
 
 // pixels to draw. We draw them in one shot.
-static xcb_rectangle_t rectangles[VDP_SCREENW*VDP_SCREENH];
+static xcb_rectangle_t rectangles[(32*8)*(24*8)];
 
 static Machine *m;
 static VDP vdp;
@@ -144,19 +144,19 @@ void draw_pixels()
     xcb_clear_area(
         conn, 0, win, 0, 0, geom->width, geom->height);
     // Figure out inner size to maximize our screen's aspect ratio
-    int psize = geom->height / VDP_SCREENH;
+    int psize = geom->height / vdp.tms.height;
-    if (geom->width / VDP_SCREENW < psize) {
+    if (geom->width / vdp.tms.width < psize) {
         // width is the constraint
-        psize = geom->width / VDP_SCREENW;
+        psize = geom->width / vdp.tms.width;
     }
-    int innerw = psize * VDP_SCREENW;
+    int innerw = psize * vdp.tms.width;
-    int innerh = psize * VDP_SCREENH;
+    int innerh = psize * vdp.tms.height;
     int innerx = (geom->width - innerw) / 2;
     int innery = (geom->height - innerh) / 2;
     free(geom);
     int drawcnt = 0;
-    for (int i=0; i<VDP_SCREENW; i++) {
+    for (int i=0; i<vdp.tms.width; i++) {
-        for (int j=0; j<VDP_SCREENH; j++) {
+        for (int j=0; j<vdp.tms.height; j++) {
             if (vdp_pixel(&vdp, i, j)) {
                 int x = innerx + (i*psize);
                 int y = innery + (j*psize);

emul/z80/sms_vdp.c

@@ -1,6 +1,11 @@
 #include <string.h>
 #include "sms_vdp.h"
 
+static bool _is_mode4(VDP *vdp)
+{
+    return (vdp->tms.regs[0]&0x4);
+}
+
 void vdp_init(VDP *vdp)
 {
     tms_init(&vdp->tms);
@@ -18,6 +23,7 @@ void vdp_cmd_wr(VDP *vdp, uint8_t val)
             vdp->tms.curaddr = TMS_VRAM_SIZE + (vdp->tms.cmdlsb&0x1f);
         } else {
             tms_cmd_wr(&vdp->tms, val);
+            vdp->tms.width = _is_mode4(vdp) ? 32*8 : 40*6;
         }
     }
 }
@@ -46,13 +52,16 @@ void vdp_data_wr(VDP *vdp, uint8_t val)
 
 uint8_t vdp_pixel(VDP *vdp, uint16_t x, uint16_t y)
 {
-    if (x >= VDP_SCREENW) {
-        return 0;
-    }
-    if (y >= VDP_SCREENH) {
-        return 0;
-    }
     TMS9918 *tms = &vdp->tms;
+    if (!_is_mode4(vdp)) {
+        return tms_pixel(tms, x, y);
+    }
+    if (x >= tms->width) {
+        return 0;
+    }
+    if (y >= tms->height) {
+        return 0;
+    }
     // name table offset
     uint16_t offset = (tms->regs[2] & 0xe) << 10;
     offset += ((y/8) << 6) + ((x/8) << 1);

emul/z80/sms_vdp.h

@@ -1,8 +1,6 @@
 #include "tms9918.h"
 
 #define VDP_CRAM_SIZE 0x20
-#define VDP_SCREENW (32*8)
-#define VDP_SCREENH (24*8)
 
 typedef struct {
     TMS9918 tms;

emul/z80/tms9918.c

@@ -1,12 +1,34 @@
+#include <stdio.h>
 #include <string.h>
 #include "tms9918.h"
 
+static uint8_t COLORS[0x10] = { // TODO: put actual color codes
+    0, // transparent
+    0, // black
+    1, // medium green
+    1, // light green
+    1, // dark blue
+    1, // light blue
+    1, // dark red
+    1, // cyan
+    1, // medium red
+    1, // light red
+    1, // dark yellow
+    1, // light yellow
+    1, // dark green
+    1, // magenta
+    1, // gray
+    1, // white
+};
+
 void tms_init(TMS9918 *tms)
 {
     memset(tms->vram, 0, TMS_VRAM_SIZE);
     memset(tms->regs, 0, 0x10);
     tms->has_cmdlsb = false;
     tms->curaddr = 0;
+    tms->width = 40*6;
+    tms->height = 24*8;
 }
 
 uint8_t tms_cmd_rd(TMS9918 *tms)
@@ -50,5 +72,19 @@ void tms_data_wr(TMS9918 *tms, uint8_t val)
 // Returns a 8-bit RGB value (0b00bbggrr)
 uint8_t tms_pixel(TMS9918 *tms, uint16_t x, uint16_t y)
 {
-    return 0; // no TMS9918 mode implemented yet
+    if ((tms->regs[1]&0x18) == 0x10 && (tms->regs[0]&0x40) == 0) {
+        // Text mode
+        uint16_t nameoff = (tms->regs[2] & 0xf) << 10;
+        uint16_t patternoff = (tms->regs[4] & 0x7) << 11;
+        uint8_t nameid = tms->vram[nameoff+(((y/8) * 40) + (x/6))];
+        uint8_t patternline = tms->vram[patternoff+(nameid*8)+(y%8)];
+        uint8_t color = tms->regs[7];
+        if ((patternline>>(8-(x%6)))&1) {
+            color >>= 4;
+        }
+        color &= 0xf;
+        return color;
+    } else { // unsupported mode
+        return 0;
+    }
 }

emul/z80/tms9918.h

@@ -13,6 +13,8 @@ typedef struct {
     uint8_t cmdlsb;
     bool has_cmdlsb;
     uint16_t curaddr;
+    uint16_t width; // in pixels
+    uint16_t height; // in pixels
 } TMS9918;
 
 void tms_init(TMS9918 *tms);