Start of TGI changes. Untested, may not work.

git-svn-id: svn://svn.cc65.org/cc65/trunk@4404 b7a2c559-68d2-44c3-8de9-860c34a00d81

libsrc/tgi/tgi_textstyle.s

@@ -1,42 +1,82 @@
 ;
-; Ullrich von Bassewitz, 22.06.2002
+; Ullrich von Bassewitz, 2009-20-30
 ;
-; void __fastcall__ tgi_textstyle (unsigned char magx, unsigned char magy,
+; void __fastcall__ tgi_textstyle (unsigned magwidth, unsigned magheight,
 ;                                  unsigned char dir);
-; /* Set the style for text output. */
+; /* Set the style for text output. The scaling factors for width and height
+;  * are 8.8 fixed point values. This means that $100 = 1 $200 = 2 etc.
+;  */
 
 
         .include        "tgi-kernel.inc"
 
-        .import         popax, incsp2
+        .import         popax
+
+
+;-----------------------------------------------------------------------------
+; Calculate either the total height or the total width of a bitmapped
+; character, depending on the value in Y. On entry, X contains the scaling
+; factor. Since it is usually small, we multiplicate by doing repeated adds.
+; The function returns zero in X and the calculated value in A.
+
+.proc   charsize_helper
+
+        lda     _tgi_fontwidth,y
+        jmp     @L2
+@L1:    clc
+        adc     _tgi_fontwidth,y
+@L2:    dex
+        bne     @L1
+        sta     _tgi_charwidth,y
+        rts
+
+.endproc
+
+
+;-----------------------------------------------------------------------------
+;
 
 .proc   _tgi_textstyle
 
-        pha
-        jsr     popax                   ; Get magx/magy in one call
-        tay
-        pla
+        sta     _tgi_textdir            ; Remember the direction
 
-; A = textdir, X = textmagx, Y = textmagy
+; The magheight value is in 8.8 fixed point. Store it and calculate a rounded
+; value for scaling the bitmapped system font in the driver.
 
-        cmp     #TGI_TEXT_HORIZONTAL
-        beq     DirOk
-        cmp     #TGI_TEXT_VERTICAL
-        beq     DirOk
-Fail:   jmp     tgi_inv_arg             ; Invalid argument
-DirOk:  cpy     #$00
-        beq     Fail                    ; Cannot have magnification of zero
-        cpx     #$00
-        beq     Fail                    ; Cannot have magnification of zero
+        jsr     popax                   ; magheight
+        sta     _tgi_textmagh+0
+        stx     _tgi_textmagh+1
+        asl     a                       ; Check value behind comma
+        bcc     @L1
+        inx                             ; Round
+@L1:    stx     _tgi_textmagh+2         ; Store rounded value
 
-; Parameter check ok, store them
+; Calculate the total height of the bitmapped font and remember it.
 
-        stx     _tgi_textmagx
-        sty     _tgi_textmagy
-        sta     _tgi_textdir
+        ldy     #1
+        jsr     charsize_helper
 
-; Call the driver, parameters are passed in registers
+; The magwidth value is in 8.8 fixed point. Store it and calculate a rounded
+; value for scaling the bitmapped system font in the driver.
 
+        jsr     popax                   ; magheight
+        sta     _tgi_textmagw+0
+        stx     _tgi_textmagw+1
+        asl     a                       ; Check value behind comma
+        bcc     @L2
+        inx                             ; Round
+@L2:    stx     _tgi_textmagw+2         ; Store rounded value
+
+; Calculate the total width of the bitmapped font and remember it.
+
+        ldy     #0
+        jsr     charsize_helper
+
+; Load values and call the driver, parameters are passed in registers
+
+        ldx     _tgi_textmagw+2
+        ldy     _tgi_textmagh+2
+        lda     _tgi_textdir
         jmp     tgi_textstyle
 
 .endproc