Marginally speed up the tty, but using eight-bit aligned font data rather than

trying to pack it cleverly. Doesn't appear to make a noticeable difference in
real life, sadly.

Author: davidgiven

arch/nc200/supervisor/tty.inc

@@ -288,6 +288,8 @@ tty_rawwrite:
     ld e, a
     ld d, 0
     add hl, de          ; hl = a*4 + a = a*5
+    add hl, de          ; hl = a*5 + a = a*6
+    add hl, de          ; hl = a*6 + a = a*7
     ld de, FONT
     add hl, de
     ; hl points at font data
@@ -296,53 +298,18 @@ tty_rawwrite:
 
     ld a, (hl)              ; XXXXX???.????????
     call draw_single_scanline
-
-    ld b, (hl)              ; ?????XXX.XX??????
-    inc hl
-    ld a, (hl)
-    srl b
-    rra
-    srl b
-    rra
-    srl b
-    rra
+    ld a, (hl)              ; XXXXX???.????????
     call draw_single_scanline
-
-    ld a, (hl)              ; ??XXXXX?
-    add a, a
-    add a, a
+    ld a, (hl)              ; XXXXX???.????????
     call draw_single_scanline
-
-    ld a, (hl)              ; ???????X.XXXX????
-    srl a
-    inc hl
-    ld a, (hl)  
-    rra
+    ld a, (hl)              ; XXXXX???.????????
     call draw_single_scanline
-
-    ld a, (hl)              ; ????XXXX.X???????
-    inc hl
-    ld b, (hl)
-    sll b
-    rla
-    add a, a
-    add a, a
-    add a, a
+    ld a, (hl)              ; XXXXX???.????????
     call draw_single_scanline
-
-    ld a, (hl)              ; ?XXXXX??
-    add a, a
+    ld a, (hl)              ; XXXXX???.????????
     call draw_single_scanline
-
-    ld b, (hl)              ; ??????XX.XXX?????
-    inc hl
-    ld a, (hl)
-    srl b
-    rra
-    srl b
-    rra
+    ld a, (hl)              ; XXXXX???.????????
     ; fall through
-
 ; On entry, the font data is in A, left justified.
 ; Font pointer is in HL.
 draw_single_scanline:
@@ -392,6 +359,7 @@ scanline_shift_amount:
     ld (L_cursor_address), hl
 
     ex de, hl           ; put font pointer back in HL
+    inc hl              ; advance to next byte of font data
     ret
 
 ; vim: sw=4 ts=4 expandtab ft=asm

arch/nc200/utils/fontconvert.c

@@ -37,33 +37,18 @@ int main(int argc, const char* argv[])
 		/* The glyph data is a 7-element array of bytes. Each byte contains
 		 * one scanline, left justified. */
 
-		uint64_t mask = 0;
-		const uint8_t* p = glyph->data;
-
+		printf("\tdb ");
 		int yy = 0;
+		const uint8_t* p = glyph->data;
 		while (yy < LINEHEIGHT)
 		{
-			/* We assume the right-most column is blank, and so only store five bits. */
-
-			mask = (mask << 5) | ((*p >> 3) & 0x1f);
+			if (yy != 0)
+				printf(", ");
+			printf("0x%02x", *p);
 			p++;
 			yy++;
 		}
-
-		/* The encoding expects 8 5-bit values in five bytes, *left* justified. */
-		while (yy < 8)
-		{
-			mask <<= 5;
-			yy++;
-		}
-
-		printf("\tdb 0x%02x, 0x%02x, 0x%02x, 0x%02x, 0x%02x ; char %d\n",
-			(uint32_t)((mask >> 32) & 0xff),
-			(uint32_t)((mask >> 24) & 0xff),
-			(uint32_t)((mask >> 16) & 0xff),
-			(uint32_t)((mask >> 8) & 0xff),
-			(uint32_t)(mask & 0xff),
-			c);
+		printf(" ; char %d\n", c);
     }
 
     return 0;