* dos: Some initial work.
* dos: Turn off buffer on stdio SDL_IOStreams.
Seeking breaks otherwise. We might be able to just fflush() before or seeking
instead?
* dos: Audio implementation using the Sound Blaster 16.
* dos: remove audio Pump interface.
Turns out DosBox-X was having trouble with the Sound Blaster or something;
standard DosBox works correctly directly from the interrupt handler, and
without doubling the buffer size.
* dos: just dump and restore the stdio buffer when seeking.
This is MUCH faster than just leaving buffering disabled, and also works
around getting bogus reads after an fseek. SDL_LoadWAV on test/sample.wav
no longer takes several seconds to finish, and comes up with the correct
data.
I wonder if we're triggering this in LoadWAV because we're malloc'ing data
between seeks/reads, and it's causing the djgpp transfer buffer to change. Or
maybe the Fat DS trick is confusing it? I don't know, I haven't had time to
debug it, it might just be a legit libc bug in djgpp too, for all I know.
* dos: Protect audio device "thread" iterations when streams are locked.
This uses an old trick we used in SDL 1.2 for MacOS Classic, which did its
audio callback in a hardware interrupt. If the audio is locked when the
interrupt fires, make a note of it and return immediately. When the lock is
released, if the interrupt has been fired, run the audio device iteration
right then.
Since there isn't a big device lock in SDL3 (available to the app, at least),
this keeps a counter of when any SDL_AudioStream is locked, which is probably
good enough.
* dos: Implemented initial video subsystem.
This uses VESA interfaces to manage the display and works with the software
renderer.
Events aren't hooked up yet, so prepare to close DosBox on each run. :)
* dos: Whoops, forgot to add these to revision control. Core and Main support.
* dos: Wired up basic filesystem support.
This gets most of the rendering examples, which use SDL_GetBasePath() to
find textures to load, working.
* dos: Fixed compiler warning.
* dos: Initial mouse support!
* dos: Move interrupt hooking code into core/dos.
* dos: Initial keyboard support!
* dos: Use a simple ring buffer for keyboard events.
Of course Quake 1 solved this better, haha. It's smart: less memory, dirt
simple, and you don't even have to worry about synchronizing with the
interrupt handler, because it's safe for both sides no matter when an
interrupt fires.
* ci: add djgpp job
[sdl-ci-filter djgpp]
[sdl-ci-artifacts]
* dos: Fix build issues after rebase onto current main
- SDL_runapp.c: Add SDL_PLATFORM_DOS to the exclusion list so the
generic
SDL_RunApp() is disabled when the DOS-specific one is compiled.
- SDL.c: Exclude SDL_Gtk_Quit() on DOS. DJGPP defines __unix__ which
sets
SDL_PLATFORM_UNIX, but DOS has no GTK/display server. The GTK source
is not compiled (CMake UNIX is false for DOS) so this was a link
error.
- sdlplatform.cmake: Add DOS case to SDL_DetectCMakePlatform so the
platform is properly detected from CMAKE_SYSTEM_NAME=DOS.
- i586-pc-msdosdjgpp.cmake: Add i386-pc-msdosdjgpp-gcc as a fallback
compiler name, since some DJGPP toolchain builds use the i386 prefix.
* Add 8-bit palette support to DOS VESA driver
* Add VBE page-flipping, state restore, and robust keyboard handling
- Implement double-buffered page-flipping for VBE modes with >1 image
page
- Save and restore full VBE state on video init/quit for clean mode
switching
- Improve DOS keyboard handling: support extended scancodes and Pause
key
- Lock ISR code/data to prevent page faults during interrupts
- Always vsync when blitting in single-buffered modes to reduce tearing
* Refactor Sound Blaster audio mixing to main loop
Move audio mixing out of IRQ handler to main loop for improved
stability and to avoid reentrancy issues. Add SDL_DOS_PumpAudio
function, update DMA buffer handling, and adjust sample rate to 22050
Hz.
Silence stale DMA buffer halves to prevent stutter during load.
* Add DOS timer support and update build config
* Add support for pre-SB16 8-bit mono Sound Blaster audio
Detect SB version and select 8-bit mono or 16-bit stereo mode.
Handle DMA and DSP setup for both SB16 and pre-SB16 hardware.
Add FORCE_SB_8BIT option for testing in DOSBox.
* Add SB Pro stereo support and simplify IRQ handler
* Add DOS joystick driver support
* Improve DOS hardware handling and clarify memory allocation
- Poll Sound Blaster DSP status instead of fixed delay after speaker-on
- Clarify DPMI conventional memory is always locked; update comments
- Document and justify DMA memory allocation strategy
- Free IRET wrapper after restoring interrupt vector to avoid leaks
- Throttle joystick axis polling to ~60 Hz to reduce BIOS timing loop
cost
- Always poll joystick buttons directly for responsiveness
* Query and use mouse sensitivity from INT 33h function 0x1B
* Add support for VESA banked framebuffer modes
Implement banked framebuffer access for VBE 1.2+ modes without LFB.
Detect and initialize banked modes, copy framebuffer data using bank
switching, and blank the framebuffer on mode set. Page-flipping is
disabled in banked mode.
* Add optional vsync to page flipping in DOS VESA driver
* Add cooperative threading support for DOS platform
* Move SoundBlaster audio mixing to SDL audio thread
* Fix DOS platform comments and workarounds for DJGPP support
* Fix SoundBlaster IRQ handling and DMA setup for DOS
- Pass IRQ number to DOS_EndOfInterrupt and handle slave PIC EOI
- Validate DMA channel from BLASTER variable
- Correct DMA page register selection for SB16
- Improve BLASTER variable parsing and error messages
- Unmask/mask IRQs on correct PIC in DOS_HookInterrupt
- Rename SDL_dosjoystick.c to SDL_sysjoystick.c
- Include SDL_main_callbacks.h in SDL_sysmain_runapp.c
- Add include guard to SDL_systhread_c.h
* Add DOS platform options and preseed cache for DJGPP
Disable unsupported SDL features when building for DOS. Add
PreseedDOSCache.cmake to pre-populate CMake cache variables for DJGPP.
* cmake: use a 8.3 naming scheme for tests on DOS
* Apply code style
* Update include/SDL3/SDL_platform_defines.h
Co-authored-by: Anonymous Maarten <madebr@users.noreply.github.com>
* Code review clean up
- Split DOS VESA mode-setting into its own file
- Replace magic numbers with named constants
- Update copyright dates to 2026
- Substract time taken by other threads form delays
* Fix DOS bugs and improve compatibility
- Disable fseeko64 for DJGPP due to broken implementation
- Refactor DOS timer delay to always yield and avoid busy-waiting
- Fix animated cursor rendering in DOS VESA backend
- Always set display mode when creating DOS VESA window
- Work around DJGPP allowing invalid file access in testfile.c
- Bump max threads to 16
- Apply workarounds for threading tests
* Add DOS platform documentation and fix a few issues
- Fix fullscreen default resolution
- Improve best mode matching
- Fix builds on GCC older than 7.0
- Fix text input events
* Fix keyboard mapping of "*"
* Fix running, and existing, under PCem
* Apply suggestions from code review
Co-authored-by: Cameron Cawley <ccawley2011@gmail.com>
* Pre-mix audio in ring buffer and copy to DMA via IRQ thread
* Video fixes and optimizations
* DOS: Fix Intel 740 and VGA compatability
* DOS: Update readme
* DOS: Fix thread ID, get GPU name
* DOS: Cap mouse range
* DOS: Map test resources to 8.3 names
* DOS: Skip unsupported WM color modes
* Fix "windowed" resolution selection
* DOS: Hide INDEX8 modes behind SDL_DOS_ALLOW_INDEX8_MODES
* Remove SDL_HINT_DOS_ALLOW_INDEX8_MODES and order modes logically
* Don't convert cursor if dest is not INDEX8
---------
Co-authored-by: Ryan C. Gordon <icculus@icculus.org>
Co-authored-by: Anonymous Maarten <anonymous.maarten@gmail.com>
Co-authored-by: Cameron Cawley <ccawley2011@gmail.com>
Co-authored-by: Gleb Mazovetskiy <glex.spb@gmail.com>
Co-authored-by: Jay Petacat <jay@jayschwa.net>
Tested-by: Cameron Cawley <ccawley2011@gmail.com>
__sync_lock_test_and_set() is designed for creating locks, not as
a general atomic exchange function. As a result, it only provides
an acquire memory barrier and isn't guaranteed to actually store
the provided value (though it does on architectures we care about).
__atomic_exchange_n() is supported on GCC/Clang for the last ~10
years, so let's use that instead if available. We will keep the
__sync_lock_test_and_set() fallback around for ancient platforms,
but add a full memory barrier to match the documented behavior.
Now apps can have persistent files available during SDL_main()/SDL_AppInit()
and don't have to mess with Emscripten-specific code to prepare the filesystem
for use.
Make use of check_include_files to be able to also include
stdint.h when checking for the headers. Fixes detection of
usbhid.h on OpenBSD.
/usr/include/usbhid.h:40:2: error: unknown type name 'uint32_t'
40 | uint32_t _usage_page;
| ^
GTK explicitly doesn't support being used setuid or setgid, and if SDL
loads and initializes GTK, GTK will exit the process if it
detects a setgid executable. This is incompatible with the historical
practice of making game executables setgid in order to write out a
shared high-score table on multi-user systems (which is security theatre
at best, because typical game runtime libraries are not hardened against
an untrusted caller, but making it regress would be a user-observable
regression in sdl2-compat).
Helps: https://github.com/libsdl-org/sdl2-compat/issues/564
Signed-off-by: Simon McVittie <smcv@debian.org>
A common use case is asking someone to clone SDL and run a test. This simplifies the instructions so we don't also have to tell them how to enable the tests. Anyone savvy can just add -DSDL_TESTS=OFF if they don't want to have them.
This PR adds support to the cmake build scripts so to allow building SDL with the Tiny C Compiler (tcc).
TinyCC supports the subset of C99 used by SDL and will complete the build once the --version-script linker flag is removed. The changes have been tested with various build configurations, including X11 and Wayland, and using tcc version 0.9.28rc 2025-10-27 mob@f4e01bfc on x86_64 Linux.
Allowing GCC/Clang to auto-vectorize with AltiVec support breaks support
for non-AltiVec compatible processors. Adding this option allows the
existing AltiVec specific code to function as it always did, but
prevents the compiler from inserting AltiVec instructions into arbitrary
codepaths that SDL can't gate off via the existing CPUInfo code.
Allows for finer grained timeout values, and fixes a FIXME.
This also drops the legacy select() fallback path in favor of presuming that poll() is always available. poll() is part of the POSIX.1-2001 standard, has been available in Unix since some time in the 1980s, the BSDs since at least the early 90s, and Linux since kernel 2.1, which predates kernel support for Pthreads. glibc also has its own emulation using select(), if necessary.
