From be32a5ffccfeacb7f176fa43b5906c4fd338b68e Mon Sep 17 00:00:00 2001 From: Stephen Horn Date: Sun, 11 Jan 2026 01:44:11 -0600 Subject: [PATCH 1/3] Enhance documentation on screen modes and memory layout Added information about video memory addresses for text and bitmap modes. --- X16 Reference - 04 - BASIC.md | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/X16 Reference - 04 - BASIC.md b/X16 Reference - 04 - BASIC.md index 89f810e..2bfe2c8 100644 --- a/X16 Reference - 04 - BASIC.md +++ b/X16 Reference - 04 - BASIC.md @@ -1520,6 +1520,11 @@ The above example overwrites an existing file on drive 9, which would be a Commo For a list of supported modes, see [Chapter 3: Editor](X16%20Reference%20-%2003%20-%20Editor.md#chapter-3-editor). The value of -1 toggles between modes $00 and $03. +The video memory for all text modes start at VERA bank 1, address $B000. (e.g. `VPOKE 1, $B000, 0`). +For mode $80, bitmap memory starts at VERA bank 0, address $0000. (e.g. `VPOKE 0, $0000, 0`). + +To understand the memory layout of text modes, refer to [Chapter 9: VERA Programmer's Reference](X16%20Reference%20-%2009%20-%20VERA%20Programmer's%20Reference.md#tile-mode-1-bpp-16-color-text-mode). All text modes use Tile mode 1 bpp (16 color text mode). + **EXAMPLE of SCREEN Statement:** ```BASIC From 2475f154da9f8b3f650b4726ea996f361b8a0b9e Mon Sep 17 00:00:00 2001 From: Stephen Horn Date: Sun, 11 Jan 2026 01:51:42 -0600 Subject: [PATCH 2/3] Enhance text modes memory layout description Added details about tile mode dimensions for text modes. --- X16 Reference - 04 - BASIC.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/X16 Reference - 04 - BASIC.md b/X16 Reference - 04 - BASIC.md index 2bfe2c8..ed13840 100644 --- a/X16 Reference - 04 - BASIC.md +++ b/X16 Reference - 04 - BASIC.md @@ -1523,7 +1523,7 @@ For a list of supported modes, see [Chapter 3: Editor](X16%20Reference%20-%2003% The video memory for all text modes start at VERA bank 1, address $B000. (e.g. `VPOKE 1, $B000, 0`). For mode $80, bitmap memory starts at VERA bank 0, address $0000. (e.g. `VPOKE 0, $0000, 0`). -To understand the memory layout of text modes, refer to [Chapter 9: VERA Programmer's Reference](X16%20Reference%20-%2009%20-%20VERA%20Programmer's%20Reference.md#tile-mode-1-bpp-16-color-text-mode). All text modes use Tile mode 1 bpp (16 color text mode). +To understand the memory layout of text modes, refer to [Chapter 9: VERA Programmer's Reference](X16%20Reference%20-%2009%20-%20VERA%20Programmer's%20Reference.md#tile-mode-1-bpp-16-color-text-mode). All text modes use Tile mode 1 bpp (16 color text mode), with 128 tiles per line and 64 lines, even though the display will not show the entire range at once. **EXAMPLE of SCREEN Statement:** From 1029fb0a85ffb6b23c4b20aab0b7bdb8816affd7 Mon Sep 17 00:00:00 2001 From: Stephen Horn Date: Sun, 11 Jan 2026 12:12:00 -0600 Subject: [PATCH 3/3] Enhance BASIC.md with references to relevant commands from SCREEN. Added references to relevant commands for editing text and bitmap data in screen modes. --- X16 Reference - 04 - BASIC.md | 23 +++++++++++++++++++++-- 1 file changed, 21 insertions(+), 2 deletions(-) diff --git a/X16 Reference - 04 - BASIC.md b/X16 Reference - 04 - BASIC.md index ed13840..bce5a33 100644 --- a/X16 Reference - 04 - BASIC.md +++ b/X16 Reference - 04 - BASIC.md @@ -1520,11 +1520,30 @@ The above example overwrites an existing file on drive 9, which would be a Commo For a list of supported modes, see [Chapter 3: Editor](X16%20Reference%20-%2003%20-%20Editor.md#chapter-3-editor). The value of -1 toggles between modes $00 and $03. +To edit text on the screen, refer to the following commands: +* [CHAR](https://github.com/X16Community/x16-docs/blob/master/X16%20Reference%20-%2004%20-%20BASIC.md#char) +* [COLOR](https://github.com/X16Community/x16-docs/blob/master/X16%20Reference%20-%2004%20-%20BASIC.md#color) +* [LOCATE](https://github.com/X16Community/x16-docs/blob/master/X16%20Reference%20-%2004%20-%20BASIC.md#locate) +* [POS](https://github.com/X16Community/x16-docs/blob/master/X16%20Reference%20-%2004%20-%20BASIC.md#pos) +* [TATTR](https://github.com/X16Community/x16-docs/blob/master/X16%20Reference%20-%2004%20-%20BASIC.md#tattr) +* [TDATA](https://github.com/X16Community/x16-docs/blob/master/X16%20Reference%20-%2004%20-%20BASIC.md#tdata) +* [TILE](https://github.com/X16Community/x16-docs/blob/master/X16%20Reference%20-%2004%20-%20BASIC.md#tile) + +To edit bitmap data in screen mode $80, refer to the following commands: +* [FRAME](https://github.com/X16Community/x16-docs/blob/master/X16%20Reference%20-%2004%20-%20BASIC.md#frame) +* [LINE](https://github.com/X16Community/x16-docs/blob/master/X16%20Reference%20-%2004%20-%20BASIC.md#line) +* [OVAL](https://github.com/X16Community/x16-docs/blob/master/X16%20Reference%20-%2004%20-%20BASIC.md#oval) +* [PSET](https://github.com/X16Community/x16-docs/blob/master/X16%20Reference%20-%2004%20-%20BASIC.md#pset) +* [RECT](https://github.com/X16Community/x16-docs/blob/master/X16%20Reference%20-%2004%20-%20BASIC.md#rect) +* [RING](https://github.com/X16Community/x16-docs/blob/master/X16%20Reference%20-%2004%20-%20BASIC.md#ring) + +Direct writing of the VERA's memory can be performed via [VPOKE](https://github.com/X16Community/x16-docs/blob/master/X16%20Reference%20-%2004%20-%20BASIC.md#vpoke). + +Details about programming for the VERA video adapter can be found in [Chapter 9: VERA Programmer's Reference](X16%20Reference%20-%2009%20-%20VERA%20Programmer's%20Reference.md). In particular, please refer to the sections on [VRAM Address Space Layout](X16%20Reference%20-%2009%20-%20VERA%20Programmer's%20Reference.md#vram-address-space-layout) and [Tile mode 1 bpp (16 color text mode)](X16%20Reference%20-%2009%20-%20VERA%20Programmer's%20Reference.md#tile-mode-1-bpp-16-color-text-mode). All text modes use Tile mode 1 bpp (16 color text mode), with 128 tiles per line and 64 lines, even though the display will not show the entire range at once. + The video memory for all text modes start at VERA bank 1, address $B000. (e.g. `VPOKE 1, $B000, 0`). For mode $80, bitmap memory starts at VERA bank 0, address $0000. (e.g. `VPOKE 0, $0000, 0`). -To understand the memory layout of text modes, refer to [Chapter 9: VERA Programmer's Reference](X16%20Reference%20-%2009%20-%20VERA%20Programmer's%20Reference.md#tile-mode-1-bpp-16-color-text-mode). All text modes use Tile mode 1 bpp (16 color text mode), with 128 tiles per line and 64 lines, even though the display will not show the entire range at once. - **EXAMPLE of SCREEN Statement:** ```BASIC