ti84: tidy up driver code

Pushed all words directly interfacing with ports and memory offsets to
low level layers. This saves us the need for keeping those variables in
runtime memory.

blk/551

@@ -1,7 +1,7 @@
 TI-84+ LCD driver
 
-Implement (emit) on TI-84+ (for now)'s LCD screen. Load with
-"555 LOAD".
+Implement (emit) on TI-84+ (for now)'s LCD screen. The low
+level part are blocks 555-557 and high level ones are 558-560.
 
 The screen is 96x64 pixels. The 64 rows are addressed directly
 with CMD_ROW but columns are addressed in chunks of 6 or 8 bits

blk/552

@@ -12,5 +12,5 @@ that line will go up 8 pixels, wrapping itself to the bottom of
 the screen.
 
 The principle is this: The active line is always the bottom
-one. Therefore, when active row is 0, Z is FNT_HEIGHT+1, when
-row is 1, Z is (FNT_HEIGHT+1)*2, When row is 8, Z is 0. (cont.)
+one. Therefore, when active row is 0, Z is FNTH+1, when row is
+1, Z is (FNTH+1)*2, When row is 8, Z is 0.              (cont.)

blk/553

@@ -8,9 +8,9 @@ only 16 characters per line, which is hardly usable.
 
 This is why we have this buffering system. How it works is that
 we're always in 8-bit mode and we hold the whole area (8 pixels
-wide by FNT_HEIGHT high) in memory. When we want to put a glyph
-to screen, we first read the contents of that area, then add
-our new glyph, offsetted and masked, to that buffer, then push
-the buffer back to the LCD. If the glyph is split, move to the
-next area and finish the job.
+wide by FNTH high) in memory. When we want to put a glyph to
+screen, we first read the contents of that area, then add our
+new glyph, offsetted and masked, to that buffer, then push the
+buffer back to the LCD. If the glyph is split, move to the next
+area and finish the job.
                                                         (cont.)

blk/555

@@ -1,15 +1,13 @@
-( Required config: TI_MEM )
-: TI_MEM+ [ TI_MEM LITN ] @ + ;
-TI_MEM : TI_MEM [ LITN ] ;
-: LCD_PORT_CMD 0x10 ; : LCD_PORT_DATA 0x11 ;
+( Required config: LCD_MEM )
+: _mem+ [ LCD_MEM LITN ] @ + ;
 : FNTW 3 ; : FNTH 5 ;
 ( Wait until the lcd is ready to receive a command. It's a bit
   weird to implement a waiting routine in asm, but the forth
   version is a bit heavy and we don't want to wait longer than
   we have to. )
-CODE LCDWAIT
+CODE _wait
     BEGIN,
-        0x10 INAn,
+        0x10 ( CMD ) INAn,
         RLA, ( When 7th bit is clr, we can send a new cmd )
     JRC, AGAIN,
 ;CODE

blk/556

@@ -1,8 +1,13 @@
 ( Current Y position on the LCD, that is, where we're going to
   spit our next glyph. )
-: LCD_CURY 0 TI_MEM+ ;
-: LCD_CURX 1 TI_MEM+ ;
-( two pixel buffers that are 8 pixels wide (1b) by FNT_HEIGHT
+: LCD_CURY 0 _mem+ ;
+: LCD_CURX 1 _mem+ ;
+( two pixel buffers that are 8 pixels wide (1b) by FNTH
   pixels high. This is where we compose our resulting pixels
   blocks when spitting a glyph. )
-: LCD_BUF 2 TI_MEM+ ;
+: LCD_BUF 2 _mem+ ;
+: _cmd 0x10 ( CMD ) PC! _wait ;
+: _data! 0x11 ( DATA ) PC! _wait ;
+: _data@ 0x11 ( DATA ) PC@ _wait ;
+: LCDOFF 0x02 ( CMD_DISABLE ) _cmd ;
+: LCDON 0x03 ( CMD_ENABLE ) _cmd ;

blk/557

@@ -1,12 +1,9 @@
-: _cmd LCD_PORT_CMD PC! LCDWAIT ;
-: _data! LCD_PORT_DATA PC! LCDWAIT ;
-: _data@ LCD_PORT_DATA PC@ LCDWAIT ;
-: LCDOFF 0x02 ( CMD_DISABLE ) _cmd ;
-: LCDON 0x03 ( CMD_ENABLE ) _cmd ;
 : _yinc 0x07 _cmd ; : _xinc 0x05 _cmd ;
-: _col! ( col -- ) 0x20 ( CMD_COL ) + _cmd ;
-: _row! ( row -- ) 0x80 ( CMD_ROW ) + _cmd ;
+: _zoff! ( off -- ) 0x40 + _cmd ;
+: _col! ( col -- ) 0x20 + _cmd ;
+: _row! ( row -- ) 0x80 + _cmd ;
 : LCD$
-    H@ TI_MEM ! FNTH 2 * 2+ ALLOT
+    H@ [ LCD_MEM LITN ] ! FNTH 2 * 2+ ALLOT
     LCDON 0x01 ( 8-bit mode ) _cmd
+    FNTH 1+ _zoff!
 ;

blk/558

@@ -10,4 +10,5 @@
 ( Changes the current line and go back to leftmost column )
 : _lf
     LCD_CURY C@ FNTH 1+ + DUP 63 > IF DROP 0 THEN
-    DUP _clrln LCD_CURY C! 0 LCD_CURX C! ;
+    DUP _clrln DUP FNTH 1+ _zoff!
+    LCD_CURY C! 0 LCD_CURX C! ;

recipes/ti84/xcomp.fs

@@ -1,6 +1,6 @@
 0x8000 CONSTANT RAMSTART
 0xb000 CONSTANT RS_ADDR
-RAMSTART 0x70 + CONSTANT TI_MEM
+RAMSTART 0x70 + CONSTANT LCD_MEM
 212 LOAD  ( z80 assembler )
 262 LOAD  ( xcomp )
 522 LOAD  ( font compiler )
@@ -12,15 +12,15 @@ RAMSTART 0x70 + CONSTANT TI_MEM
 CURRENT @ XCURRENT !
 
 282 LOAD  ( boot.z80 )
-555 LOAD  ( ti.z80 )
 393 LOAD  ( icore low )
+555 557 LOADR ( ti low )
 415 LOAD  ( icore high )
 (entry) ~FNT CPFNT3x5
 (entry) _
 ( Update LATEST )
 PC ORG @ 8 + !
 422 437 XPACKR ( core )
-556 560 XPACKR ( ti )
+558 560 XPACKR ( ti high )
 438 446 XPACKR ( print fmt )
 ," : _ LCD$ LIT< Hello (print) LIT< World! (print) BYE ; _ "
 ORG @ 256 /MOD 2 PC! 2 PC!