SDK v0.11.8

Bug Fixes

• neslib -- Fixed almost completely broken vram_inc implementation.

Miscellaneous

• The release packages now include the headers, libraries, and tools needed to build rust-mos. This should allow that project to consume our binary releases rather than rebuilding llvm-mos from scratch.

SDK v0.11.7

New Features and Improvements

• Partial implementations of C++ headers <algorithm>, <array>, <iterator>, <utility>, and <limits>. Thanks, @pfusik !

• The assembler now accepts uppercase register names (i.e., LDA (32),Y, not just LDA (32),y). Thanks, @pfusik !

• The default C64 target now swaps out the BASIC ROM before program start, which increases usable contiguous memory to 50KiB. Thanks, @OskarLinde !

• Merged from upstream LLVM.

Bug Fixes

• Setting PRG-(NV)RAM or CHR-(NV)RAM sizes to zero on NES targets now works properly. Previously, zero would be fed into the formula used to compute shift counts for the iNES 2.0 header, but zero is out of the legal range of those formula.

SDK v0.11.6

New targets

• The new atari8-stdcart target now allows compiling to a standard 8KiB or 16KiB Atari 8-bit cartridge. Thanks, @cwedgwood !

Assembler improvements

• INC A, INA, DEA, and DEC A spellings are now supported for INC and DEC. Thanks, @pfusik !

Optimizations

• The compiler now spends more time on Loop Strength Reduction, the most important loop optimization pass. Loop quality is particularly important on the 6502, especially relative to overall program size, so we can afford to spend longer on it. Overall, it doesn't seem to impact the compile times that much, but we see a sizable gain on some benchmarks.

Cleanup

• The compiler now uses the .zeropage directive to introduce imaginary registers when generating assembly output. This means that uses of imaginary registers are no longer wrapped with mos8(...), which makes assembly listings considerably easier to read.

SDK v0.11.5

New features

• Added a .zeropage <symbol> directive to allow marking external symbols as belonging to the zero page, much like cc65's .importzp. This is more ergonomic than wrapping each usage with mos8(...), and it paves the way to more readable compiler-generated assembly as well.

Bug fixes

• The BRK() macro in 6502.h now contains a nop after the brk. This allows the brk to return successfully to the program afterwards, which makes this more useful when temporarily stopping the program to debug it.
• Fixed a stray write to the zero page in the MMC1 bank handler. A symbol was accidentally placed in absolute memory rather than the zero page, but the memory was referenced using just the low byte.

SDK v0.11.4

Bug fixes

• Fixed transposition of the x and y arguments in neslib's scroll().
• Fixed MMC1 issue where use of certain banking routines might not register the corresponding NMI handler.
• Pinned Ubuntu and Windows versions to the previous release.
  • Generally, systems libraries offer backwards, but not forwards, compatibility, so a binary built against newer system libraries may not run against an older system. Accordingly, we now build against the oldest supported Ubuntu and Windows versions offered by Github Actions.
• Prevent post-link tools from running when using -Wl,--lto-emit-asm. llvm-mos/llvm-mos#256
• Fix crash in specific increment/decrement optimization scenario. llvm-mos/llvm-mos#257
• Don't allocate variables covered by #pragma clang section to the zero page. This would break later, as the implicit section would override the zero page tag, but the code would still use 8-bit references.
• Don't link against Github Action's libxml and zlib. These aren't reliably available on all target platforms, and they're used for niche functionality in LLVM.

SDK v0.11.2

New Features

• Added -fnonreentrant, -freentrant, __attribute__((nonreentrant)), and __attribute__((reentrant)). The -fnonreentrant Clang flag and __attribute__((nonreentrant)) function attribute directly tell the compiler that it can safely assume that no more than one instance of a given function can simultaneously be active, whether via recursion or interrupt handling. The compiler flag applies to every function in the given module. The -freentrant and __attribute__((reentrant)) flags produce the current default behavior; the compiler cannot assume nonreentrancy, but it still may be able to prove that a given function is safe. The function attributes take precedence over the compiler flags.

Optimizations

• Fixed llvm-mos/llvm-mos#244. This can prevent spilling and filling of immediate loads, preferring instead to reissue the load.
• Fixed llvm-mos/llvm-mos#245, a minor load elision optimization.

SDK v0.11.1

New targets

• The NES MMC3 target is now complete and tested.

Bug fixes

• #89 - Check for the batch file version for mos-clang platforms

  • This fixed an issue that prevented successful builds using the CMake toolchain config on Windows. Thanks @jroweboy !

• llvm-mos/llvm-mos#243 - Inline asm branch to wrong location

  • This fixed an issue where the assembler would fail to emit a relocation for unknown branch targets, which could cause invalid code generation. Only affects assembler and inline assembly.

Optimizations

• Small functions in the NES neslib and nesdoug libraries were rewritten in C. Combined with LTO, this allows them to be inlined. Given that a number of functions are essentially accessors and mutators for global state, this can dramatically improve the code sequences that involve them.

Misc

• Integrated changes from upstream LLVM.

• llvm-objdump now prints instruction arguments in hexadecimal by default.

SDK v0.11.0

Breaking changes

• .init priorities have been rescaled from 10, 20 to 100, 200, to give more room between init events.

• Famitone2 no longer automatically initializes sounds using sounds_data and music using music_data. Users should expcility call initialization functions before using the library. This allows banked use cases to work, since they depend on initializing the library more than once.

Bug fixes

• Fixed a pair of issues (llvm-mos/llvm-mos#236, llvm-mos/llvm-mos#237) which caused codegen to hang on 128-bit operations. This affected the rust-mos standard library.

• Fixed llvm-mos/llvm-mos#131, which caused Mac builds to fail when using -DBUILD_SHARED_LIBS=ON. Thanks, @pfusik !

• Fixed an issue, also found by @pfusik , where a comparison with zero would be incorrectly elided with a preceding inline assembly fragment, which may not have set N and Z to the expected values.

Optimizations

• The neslib library has been broken up somewhat so that NMI and init functionality for unused portions can be better GCed away.

Library features

• Famitone2 now includes a library that provides fixed-bank wrappers, for when the library is in a bank. It also now supports setting the banks for music and data, for when these are in a different bank from the library.

• NES libraries now dynamically build a NMI routine based on what's actually linked into the program. The user can override this default NMI routine and provide their own. To facilitate this, all NMI routines provided by libraries are accessible via a simple JSR.

• NES targets now have a generic .chr_rom section that allows completely controlling the layout of CHR-ROM banks. This is useful if you want to use a single binary file to set all banks.

• The cbm_k functions have been added to cbm.h for all Commodore targets. #87. Thanks, @cnelson20 !

• getchar() has now been implemented for Atari8. #88. Thanks, @pfusik !

• There are now BRK(), CLI(), and SEI() macros that generate the respective instructions, available in 6502.h.

SDK v0.10.1

Bug Fixes

• Fixed llvm-mos/llvm-mos#238 - Linkage to non-existent libzstd.1.dylib on MacOS: Breakage in MacOS binaries due to unintentional dependency on Homebrew ZSTD library present on Github Actions builders, but not in stock MacOS image.
• Fixed llvm-mos/llvm-mos#235 - @llvm.smul.with.overflow.i64 hangs compiler
• Fixed llvm-mos/llvm-mos#234 - @llvm.fshl hangs compiler: This fixes an issue where detecting an integer rotation pattern produced an infinite loop in the backend.

SDK v0.10.0

Breaking changes

• Removed stub PPU functions from NES target.

New targets

• Added NES-CNROM target.

New functionality

• Added padlib and zaplib functions to nesdoug library.
• Added banking library to MMC1's libc.
• The third byte of PRG VMAs is now the bank number.
• Neslib's NMI handler and famitone2 now support PRG and CHR banking.

Bug fixes

• Unhandled addresses are now reported to Mesen as "register labels".
• Various bug-fixes to neslib, nesdoug, and famitone2 libraries.

Optimizations

• The legalizer now uses known bits information to select 8-bit addressing whenever it can prove that the high 8 bits of a pointer offset are all zero.
• Callee-saved registers are no longer saved or restored for functions that can be proven never to return. (Thanks Anshil!)