[metal] Start exploring graphical video modes for VGA console #637

tkchia · 2022-09-22T22:19:28Z

To do:

optionally dump a list of usable VESA VBE video modes — including any graphics frame buffer video modes — at startup (✓ https://github.com/tkchia/cosmopolitan/commit/8baea6aefefacbf3fe7c643f7da791177cbe06ee, https://github.com/tkchia/cosmopolitan/commit/d5eb6c32f27cbbac3c620bcbcaba12a8b4abb379)
- this can be triggered at boot time by holding down one of the ⇧ Shift keys
actually switch to a graphics video mode (✓ https://github.com/tkchia/cosmopolitan/commit/43b2973a04506e2b1c053f65eed87a610ae0afa2)
maybe do something interesting in the new mode (✓ https://github.com/tkchia/cosmopolitan/commit/cf79923df165071552ab63197e3f92d5a58e0197)
maybe allow user to select which video mode to switch to (✓ https://github.com/tkchia/cosmopolitan/commit/e6e56a74e49e83d78d510fc24f44b501eb5e4ed7)

Edit 2022-09-26: in addition:

tweak handling of physical memory → virtual memory mapping, to allow graphics frame buffer outside base memory (✓ https://github.com/tkchia/cosmopolitan/commit/8089876c5121986e50f389bdb6d326a521e907cd, https://github.com/tkchia/cosmopolitan/commit/388c4f606036112aa2f2521e628ab0ca020d719f, https://github.com/tkchia/cosmopolitan/commit/0d594ecd85aaf654b815ce983852d464ed4efc0d)
- factor __invert_memory() into two routines, to make it easier for other libc routines to create their own negative address mappings
- tweak __invert_memory() to map only the usable memory as given in the 0xe820 memory map, and no more
- arrange for VGA console initialization to map video memory separately into virtual memory (in case needed)
- rename libc/vga/vga-init.S to libc/vga/rlinit-vga.S, to reduce confusion as to the module's purpose

- Factor __invert_memory() into two routines, to make it easier for other libc routines to create their own negative address mappings - Tweak __invert_memory() to map only the usable memory as given in the 0xe820 memory map, and no more - Arrange for VGA console initialization to map video memory separately into virtual memory (in case needed) - Rename libc/vga/vga-init.S to libc/vga/rlinit-vga.S, to reduce confusion as to the module's purpose

This should hopefully help us adapt the VGA console code, to work with video modes other than 80 × 25 × 16 text.

tkchia · 2022-09-23T14:08:14Z

Is there any good way for me to mark this pull request as being "dependent" on another pull request (namely, #636)? I think I will need the functionality I implemented in #636 in order to move forward on this PR.

If the user holds down one of the Shift keys at boot time, the program will dump a list of all usable VESA VBE video modes on the VGA console.

from VESA video mode list

Video mode switching works. Character output, not so much. (The tty code still thinks it is writing text mode characters.)

tkchia · 2022-09-26T19:09:41Z

Video mode switching now works. Character output, not so much.

ghaerr · 2022-09-26T20:04:42Z

Hello @tkchia,

Video mode switching now works.

Wow, super nice work, and great display!

Character output, not so much.

I have just completed a text and graphics console emulator for Cosmopolitan, based on SDL, which will compile on Linux and macOS. I have used this to further some of the ideas discussed in #638. In particular, it includes a glyph drawing function and memory-based font that will work for all the modes shown in your screenshot above. I will post that code shortly, which should allow you to rapidly get graphical console text output running in short order.

Thank you!

tkchia · 2022-09-26T20:15:17Z

Hello @ghaerr,

Thanks! I look forward to seeing what you have.

tkchia · 2022-09-26T20:22:42Z

Hello @ghaerr,

Incidentally, have you sent a copyright assignment or copyright disclaimer e-mail to @jart yet (#616 (comment))? I think this will be needed to ultimately get your contributions included upstream. Thank you!

ghaerr · 2022-09-26T20:35:21Z

Hello @tkchia,

Incidentally, have you sent a copyright assignment or copyright disclaimer e-mail to @jart yet

Yes I have. However, seeing your progress on the VGA console in the past 10 days, I thought to at least post something that you might use ASAP, to allow you to continue making progress at full speed :)

I think this will be needed to ultimately get your contributions included upstream.

Yes. In this particular case, the "console emulator" isn't actually a Cosmopolitan binary, as it uses the (fairly extensive and not-likely-easily ported) SDL library to allow for graphical display and proper emulation of 32bpp, 24bpp and 16bpp framebuffer formats, and possibly to be used in the Cosmopolitan test suite for upcoming graphical library routines. I am not sure how @jart wants things like this organized.

Thank you!

paulwratt · 2022-09-29T10:57:52Z

in that video mode output on the headers line change wid & ht to (capital) X & Y (space pad them if need be) - that will improve "eye" recognition and you dont need to understand english to decypher what they refer to.

EDIT: alternatively you could place (centered) x between the values and change header to (centered) size (or X x Y or X Y), eg:

     mode#      size    bpp     mode#     X x Y    bpp     mode#     X   Y    bpp
  G 0x410d   320 x 200   15  G 0x410e   320 x 200   16  G 0x4110   640 x 480   15
  G 0x4116  1024 x 768   15  G 0x4113   800 x 600   16  G 0x4114   800 x 600   15
  G 0x411a  1280 x 1024  16  G 0x411d  1600 x 1200  15  G 0x411e  1600 x 1200  16
  T 0x4002    80 x 25     4  T 0x4003    80 x 25     4

NOTE: there are no extended text modes in there? (80x50, 256 color (8bpp), 132x50, etc)

@paulwratt

Following @paulwratt's suggestion at #637 (comment)

tkchia · 2022-09-30T08:49:57Z

Hello @paulwratt,

EDIT: alternatively you could place (centered) x between the values and change header to (centered) size (or X x Y or X Y), eg:

I think I will leave that as an exercise for whoever is interested. 🙂

NOTE: there are no extended text modes in there? (80x50, 256 color (8bpp), 132x50, etc)

Strangely no, as far as I can tell. There are also no (directly supported) extended text modes on the actual (non-VM) PC which I am testing with.

Mode 0x4013 or 0x0013 — i.e. the MCGA 320 × 200 × 256-colour video mode — does exist, but my code filters out video modes that are not direct colour modes, so it is not listed.

Thank you!

tkchia · 2022-09-30T08:50:59Z

OK — the user can now select which video mode to switch to, after pressing the ⇧ Shift key at startup.

I also added a quick test routine to have the protected mode code draw a glyph (in two different colours) in the middle of the screen.

jart

I'm loving watching the progress unfold so quickly on this. You're doing fabulous work. You're making Cosmopolitan a true operating system!

jart · 2022-10-02T08:40:25Z

libc/vga/rlinit-vesa.S

+_rlinit_vesa:
+	push	%es
+	pushw	$0
+	testb	$0b00000011,0x0417	# read keyboard shift state (as


I've re-enabled the Wiki feature on this repository. Knowledge like a magic shift key for VGA config would be a good thing to have documented there! Put anything on the wiki you want!

jart · 2022-10-02T08:43:47Z

libc/vga/rlinit-vesa.S

+//	@return	CF = 0 if we decided to set a new video mode, CF = 1 otherwise
+
+	.real
+	.code16


[high level optional suggestion] You are so good at writing real mode code. But is there no other way? Is it possible to control this stuff from long mode using i/o ports? Surely there's got to be some i/o ports that are generally well-supported and well-defined on x86-64 PCs and servers. Because it'd be nice to have more stuff written in C if possible rather than depending on BIOS interfaces if we don't have to. Our support vector is 2006+ so if a consensus exists after that year for i/o ports let's use it.

Hello @jart,

This is (still) beyond my capability at the moment, I am afraid, if it is possible. That is, I have not quite found a simple way to reliably switch modes, without going through VESA (in the case of legacy BIOS boot) or EFI GOP (in the case of UEFI boot). I suspect that at least some parts of the mode switching must be done differently for different graphics cards.

Thank you!

That's fine. I'm sure as the work evolves it'll attract more people who can help us!

jart · 2022-10-02T08:48:21Z

libc/vga/writev-vga.c

@@ -58,9 +52,194 @@ ssize_t sys_writev_vga(struct Fd *fd, const struct iovec *iov, int iovlen) {
  return wrote;
 }

+static void _vga_init_test(void *vid_buf, unsigned char vid_type,


This looks like code we'll probably want to TODO move into examples/ soon. This isn't needed for production code, correct?

@jart : yes, it is not really needed. Thank you!

tkchia added 2 commits September 22, 2022 18:28

Bare metal VGA: pass video mode information via struct mman

388c4f6

This should hopefully help us adapt the VGA console code, to work with video modes other than 80 × 25 × 16 text.

tkchia marked this pull request as draft September 23, 2022 14:04

tkchia marked this pull request as ready for review September 23, 2022 14:05

tkchia marked this pull request as draft September 23, 2022 14:11

tkchia marked this pull request as ready for review September 24, 2022 22:14

tkchia mentioned this pull request Sep 26, 2022

Bare metal: tweaks pertaining to physical memory handling #636

Closed

tkchia changed the title ~~Bare metal VGA: detect graphics video modes at startup~~ [metal] Start exploring graphical video modes for VGA console Sep 26, 2022

tkchia added 4 commits September 26, 2022 18:23

Bare metal VGA: allow for 64-bit video frame buffer address

0d594ec

Bare metal VGA: optionally dump VESA video mode list at startup

8ed7d4d

If the user holds down one of the Shift keys at boot time, the program will dump a list of all usable VESA VBE video modes on the VGA console.

Bare metal VGA: filter out non-framebuffer graphics modes

d5eb6c3

from VESA video mode list

[metal] Switch to graphics video on Shift key at boot (experimental)

43b2973

Video mode switching works. Character output, not so much. (The tty code still thinks it is writing text mode characters.)

ghaerr mentioned this pull request Sep 27, 2022

Bare metal enhancements discussion #638

Open

tkchia added 2 commits September 27, 2022 21:31

[metal] Fix bug in video mode switch, & document data structure

596f7d1

[metal] Let user choose video mode after pressing Shift on boot

e6e56a7

tkchia added 2 commits September 30, 2022 07:26

[metal] Try drawing an "A" glyph once in a graphics video mode

cf79923

[metal] When listing VESA video modes, say "X" "Y" not "wid" "ht"

f8eb68a

Following @paulwratt's suggestion at #637 (comment)

[metal] Start refactoring VGA console code, for graphics modes

d278e32

jart reviewed Oct 2, 2022

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jart approved these changes Oct 2, 2022

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jart merged commit ecb2ef7 into jart:master Oct 2, 2022

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[metal] Start exploring graphical video modes for VGA console #637

[metal] Start exploring graphical video modes for VGA console #637

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[metal] Start exploring graphical video modes for VGA console #637

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