From 275e0d7ec8acb12535d2e46ba0284e8bfdf45746 Mon Sep 17 00:00:00 2001
From: Peter Weingartner <pweingar@gmail.com>
Date: Tue, 24 Dec 2024 19:58:13 -0500
Subject: [PATCH] Basic scroll case speed-up

---
 src/C256/extras.s  | 39 +++++++++++++++++++++++++++++
 src/dev/txt_f256.c | 61 ++++++++++++++++++++++++++++++++++++++++++++--
 src/version.h      |  2 +-
 3 files changed, 99 insertions(+), 3 deletions(-)

diff --git a/src/C256/extras.s b/src/C256/extras.s
index 53b4811..7c5e714 100644
--- a/src/C256/extras.s
+++ b/src/C256/extras.s
@@ -1,7 +1,10 @@
 				.public restart_cli
+				.public io_copy_down
+				.public io_copy_up
 
 				.extern proc_shell_address
             	.extern _Vfp
+				.extern _Dp
             	.extern _DirectPageStart
 
 #ifndef __CALYPSI_DATA_MODEL_SMALL__
@@ -11,6 +14,42 @@
               	.section stack
 				.section farcode
 
+;
+; void io_copy_down(uint16_t count, uint16_t dest, uint16_t src)
+;
+io_copy_down:	pha
+				phx
+				phy
+				phb
+
+				ldy dp:.tiny (_Dp)
+				ldx dp:.tiny (_Dp+4)
+				mvn #0xf0, #0xf0
+
+				plb
+				ply
+				plx
+				pla
+				rtl
+
+;
+; void io_copy_up(uint16_t count, uint16_t dest, uint16_t src)
+;
+io_copy_up:		pha
+				phx
+				phy
+				phb
+
+				ldy dp:.tiny (_Dp)
+				ldx dp:.tiny (_Dp+4)
+				mvp #0xf0, #0xf0
+
+				plb
+				ply
+				plx
+				pla
+				rtl
+
 ;
 ; Reset the stack to the initial value.
 ; Reset the direct page and data bank registers
diff --git a/src/dev/txt_f256.c b/src/dev/txt_f256.c
index 551c14a..4b47a50 100644
--- a/src/dev/txt_f256.c
+++ b/src/dev/txt_f256.c
@@ -406,15 +406,44 @@ static short txt_f256_set_color(unsigned char foreground, unsigned char backgrou
     return 0;
 }
 
+extern void io_copy_down(uint16_t count, uint16_t dest, uint16_t src);
+extern void io_copy_up(uint16_t count, uint16_t dest, uint16_t src);
+
+/**
+ * Scroll the screen for the most common case: full screen scrolls up by one full row.
+ */
+static void txt_f256_scroll_simple() {
+	uint16_t rows = f256_max_size.height;
+	uint16_t columns = f256_max_size.width;
+	uint16_t count = (rows - 1) * columns;
+
+	// Move the rows up
+	uint16_t text_dest = (uint16_t)((uint32_t)tvky_text_matrix & 0xffff);
+	uint16_t text_src = text_dest + columns;
+	io_copy_down(count, text_dest, text_src); 
+
+	uint16_t color_dest = (uint16_t)((uint32_t)tvky_color_matrix & 0xffff);
+	uint16_t color_src = color_dest + columns;
+	io_copy_down(count, color_dest, color_src); 
+
+	// Clear the bottom line
+	for (uint16_t i = count; i < rows * columns; i++) {
+		tvky_text_matrix[i] = ' ';
+		tvky_color_matrix[i] = f256_color;
+	}
+}
+
 /**
  * Scroll the text in the current region
+ * 
+ * Supports the general case
  *
  * @param screen the number of the text device
  * @param horizontal the number of columns to scroll (negative is left, positive is right)
  * @param vertical the number of rows to scroll (negative is down, positive is up)
  */
-static void txt_f256_scroll(short horizontal, short vertical) {
-    short x, x0, x1, x2, x3, dx;
+static void txt_f256_scroll_complex(short horizontal, short vertical) {
+	short x, x0, x1, x2, x3, dx;
     short y, y0, y1, y2, y3, dy;
 
     /*
@@ -468,6 +497,18 @@ static void txt_f256_scroll(short horizontal, short vertical) {
         row_src += delta_y;
         int offset_dst = row_dst + x0 - dx;
         int offset_src = row_src + horizontal + x0 - dx;
+
+		// Move the rows up
+		uint16_t count = x2 - x0;
+
+		// uint16_t text_dest = (uint16_t)((uint32_t)tvky_text_matrix & 0xffff) + offset_dst;
+		// uint16_t text_src =  (uint16_t)((uint32_t)tvky_text_matrix & 0xffff) + offset_src;
+		// txt_f256_copy(text_dest, text_src, count); 
+
+		// uint16_t color_dest = (uint16_t)((uint32_t)tvky_color_matrix & 0xffff) + offset_dst;
+		// uint16_t color_src = (uint16_t)((uint32_t)tvky_color_matrix & 0xffff) + offset_src;
+		// txt_f256_copy(color_dest, color_src, count); 
+
         for (x = x0; x != x2; x += dx) {
             offset_dst += dx;
             offset_src += dx;
@@ -499,6 +540,22 @@ static void txt_f256_scroll(short horizontal, short vertical) {
         }
     } 
 }
+/**
+ * Scroll the text in the current region
+ *
+ * @param horizontal the number of columns to scroll (negative is left, positive is right)
+ * @param vertical the number of rows to scroll (negative is down, positive is up)
+ */
+static void txt_f256_scroll(short horizontal, short vertical) {
+	// If we're scrolling up one, and the region is the full screen, use a faster scrolling routine
+	if ((horizontal == 0) && (vertical == 1) &&
+		(f256_region.origin.x == 0) && (f256_region.origin.y == 0) &&
+		(f256_region.size.width == f256_max_size.width) && (f256_region.size.height == f256_max_size.height)) {
+		txt_f256_scroll_simple();
+	} else {
+		txt_f256_scroll_complex(horizontal, vertical);
+	}
+}
 
 /**
  * Fill the current region with a character in the current color
diff --git a/src/version.h b/src/version.h
index 4bc6355..c182d22 100644
--- a/src/version.h
+++ b/src/version.h
@@ -7,6 +7,6 @@
 
 #define VER_MAJOR 1
 #define VER_MINOR 1
-#define VER_BUILD 9
+#define VER_BUILD 11
 
 #endif