Move open coding of construction of attributes for cut regions and

text cursors to functions so that it is easier to fix and improve.
This commit doesn't fix anything except for removing unnecessary
complications and adding comments.

sys/dev/syscons/scvgarndr.c

@@ -344,6 +344,46 @@ static int vga_aspect_scale= 100;
 SYSCTL_INT(_machdep, OID_AUTO, vga_aspect_scale, CTLFLAG_RW,
     &vga_aspect_scale, 0, "Aspect scale ratio (3:4):actual times 100");
 
+static u_short
+vga_flipattr(u_short a, int blink)
+{
+	if (blink)
+		a = (a & 0x8800) | ((a & 0x7000) >> 4) |
+		    ((a & 0x0700) << 4);
+	else
+		a = ((a & 0xf000) >> 4) | ((a & 0x0f00) << 4);
+	return (a);
+}
+
+static u_short
+vga_cursorattr_adj(u_short a, int blink)
+{
+	/*
+	 * !blink means pixel mode, and the cursor attribute in that case
+	 * is simplistic reverse video.
+	 */
+	if (!blink)
+		return (vga_flipattr(a, blink));
+
+	/*
+	 * The cursor attribute is usually that of the underlying char
+	 * with the bg changed to white.  If the bg is already white,
+	 * then the bg is changed to black.  The fg is usually not
+	 * changed, but if it is the same as the new bg then it is
+	 * changed to the inverse of the new bg.
+	 */
+	if ((a & 0x7000) == 0x7000) {
+		a &= 0x8f00;
+		if ((a & 0x0700) == 0)
+			a |= 0x0700;
+	} else {
+		a |= 0x7000;
+		if ((a & 0x0700) == 0x0700)
+			a &= 0xf000;
+	}
+	return (a);
+}
+
 static void
 vga_setmdp(scr_stat *scp)
 {
@@ -436,8 +476,7 @@ vga_txtdraw(scr_stat *scp, int from, int count, int flip)
 		for (p = sc_vtb_pointer(&scp->scr, from); count-- > 0; ++from) {
 			c = sc_vtb_getc(&scp->vtb, from);
 			a = sc_vtb_geta(&scp->vtb, from);
-			a = (a & 0x8800) | ((a & 0x7000) >> 4) 
+			a = vga_flipattr(a, TRUE);
-				| ((a & 0x0700) << 4);
 			p = sc_vtb_putchar(&scp->scr, p, c, a);
 		}
 	} else {
@@ -482,8 +521,7 @@ draw_txtcharcursor(scr_stat *scp, int at, u_short c, u_short a, int flip)
 		if (scp->curs_attr.base >= h)
 			return;
 		if (flip)
-			a = (a & 0x8800)
+			a = vga_flipattr(a, TRUE);
-				| ((a & 0x7000) >> 4) | ((a & 0x0700) << 4);
 		bcopy(font + c*h, font + sc->cursor_char*h, h);
 		font = font + sc->cursor_char*h;
 		for (i = imax(h - scp->curs_attr.base - scp->curs_attr.height, 0);
@@ -496,18 +534,9 @@ draw_txtcharcursor(scr_stat *scp, int at, u_short c, u_short a, int flip)
 	} else
 #endif /* SC_NO_FONT_LOADING */
 	{
-		if ((a & 0x7000) == 0x7000) {
+		a = vga_cursorattr_adj(a, TRUE);
-			a &= 0x8f00;
-			if ((a & 0x0700) == 0)
-				a |= 0x0700;
-		} else {
-			a |= 0x7000;
-			if ((a & 0x0700) == 0x0700)
-				a &= 0xf000;
-		}
 		if (flip)
-			a = (a & 0x8800)
+			a = vga_flipattr(a, TRUE);
-				| ((a & 0x7000) >> 4) | ((a & 0x0700) << 4);
 		sc_vtb_putc(&scp->scr, at, c, a);
 	}
 }
@@ -544,9 +573,7 @@ vga_txtcursor(scr_stat *scp, int at, int blink, int on, int flip)
 		} else {
 			cursor_attr = sc_vtb_geta(&scp->vtb, at);
 			if (flip)
-				cursor_attr = (cursor_attr & 0x8800)
+				cursor_attr = vga_flipattr(cursor_attr, TRUE);
-					| ((cursor_attr & 0x7000) >> 4)
-					| ((cursor_attr & 0x0700) << 4);
 			if (scp->status & VR_CURSOR_ON)
 				sc_vtb_putc(&scp->scr, at,
 					    sc_vtb_getc(&scp->vtb, at),
@@ -875,13 +902,10 @@ vga_vgadraw_direct(scr_stat *scp, int from, int count, int flip)
 	for (i = from; count-- > 0; ++i) {
 		a = sc_vtb_geta(&scp->vtb, i);
 
-		if (flip) {
+		if (flip)
-			col1 = (((a & 0x7000) >> 4) | (a & 0x0800)) >> 8;
+			a = vga_flipattr(a, TRUE);	/* XXX */
-			col2 = (((a & 0x8000) >> 4) | (a & 0x0700)) >> 8;
+		col1 = (a & 0x0f00) >> 8;
-		} else {
+		col2 = (a & 0xf000) >> 12;
-			col1 = (a & 0x0f00) >> 8;
-			col2 = (a & 0xf000) >> 12;
-		}
 
 		e = d;
 		f = &(scp->font[sc_vtb_getc(&scp->vtb, i) * scp->font_size]);
@@ -932,13 +956,10 @@ vga_vgadraw_planar(scr_stat *scp, int from, int count, int flip)
 		count = scp->xsize*scp->ysize - from;
 	for (i = from; count-- > 0; ++i) {
 		a = sc_vtb_geta(&scp->vtb, i);
-		if (flip) {
+		if (flip)
-			col1 = ((a & 0x7000) >> 4) | (a & 0x0800);
+			a = vga_flipattr(a, TRUE);	/* XXX */
-			col2 = ((a & 0x8000) >> 4) | (a & 0x0700);
+		col1 = a & 0x0f00;
-		} else {
+		col2 = (a & 0xf000) >> 4;
-			col1 = (a & 0x0f00);
-			col2 = (a & 0xf000) >> 4;
-		}
 		/* set background color in EGA/VGA latch */
 		if (bg != col2) {
 			bg = col2;
@@ -1002,13 +1023,12 @@ draw_pxlcursor_direct(scr_stat *scp, int at, int on, int flip)
 
 	a = sc_vtb_geta(&scp->vtb, at);
 
-	if (flip) {
+	if (flip)
-		col1 = ((on) ? (a & 0x0f00) : ((a & 0xf000) >> 4)) >> 8;
+		a = vga_flipattr(a, FALSE);
-		col2 = ((on) ? ((a & 0xf000) >> 4) : (a & 0x0f00)) >> 8;
+	if (on)
-	} else {
+		a = vga_cursorattr_adj(a, FALSE);
-		col1 = ((on) ? ((a & 0xf000) >> 4) : (a & 0x0f00)) >> 8;
+	col1 = (a & 0x0f00) >> 8;
-		col2 = ((on) ? (a & 0x0f00) : ((a & 0xf000) >> 4)) >> 8;
+	col2 = a >> 12;
-	}
 
 	f = &(scp->font[sc_vtb_getc(&scp->vtb, at) * scp->font_size +
 	      scp->font_size - scp->curs_attr.base - 1]);
@@ -1048,18 +1068,16 @@ draw_pxlcursor_planar(scr_stat *scp, int at, int on, int flip)
 	/* set background color in EGA/VGA latch */
 	a = sc_vtb_geta(&scp->vtb, at);
 	if (flip)
-		col = (on) ? ((a & 0xf000) >> 4) : (a & 0x0f00);
+		a = vga_flipattr(a, FALSE);
-	else
+	if (on)
-		col = (on) ? (a & 0x0f00) : ((a & 0xf000) >> 4);
+		a = vga_cursorattr_adj(a, FALSE);
+	col = (a & 0xf000) >> 4;
 	outw(GDCIDX, col | 0x00);	/* set/reset */
 	outw(GDCIDX, 0xff08);		/* bit mask */
 	writeb(d, 0);
 	c = readb(d);			/* set bg color in the latch */
 	/* foreground color */
-	if (flip)
+	col = a & 0x0f00;
-		col = (on) ? (a & 0x0f00) : ((a & 0xf000) >> 4);
-	else
-		col = (on) ? ((a & 0xf000) >> 4) : (a & 0x0f00);
 	outw(GDCIDX, col | 0x00);	/* set/reset */
 	f = &(scp->font[sc_vtb_getc(&scp->vtb, at)*scp->font_size
 		+ scp->font_size - scp->curs_attr.base - 1]);