BREAKING CHANGE: the order of these operations was inconsistent
across the different VMs. Go VM was the only one to first modulate
and then apply note tracking multiplication. But that made most
sense. So now all different VM versions work in this same way.
The sample-based oscillators converted the samplepos to an integer
and did samplepos < loop_end comparison to check if we are past
looping. Unfortunately, the < comparison was done in signed math.
Normally, this should never happen, but if the x87 FPU stack
overflowed exactly at right position, we then got 0x80000000 in
samplepos, which is equal to -2147483648. Thus, we considered that
sample is not looping and read the sample table at position
-2147483648, well out of bound. TL;DR changing jl to jb makes sure
we always wrap within to sample table, no matter what.
Fixes#149.
This demonstrates a bug found by Virgill:
the x86 templates optimize away the phase
modulation when all phases are set to 0,
but the unisons need the phase modulation
internally to offset the phase of the different
unison oscillators.
There is a new "sync" opcode that saves the top-most signal every 256 samples to the new "syncBuffer" output. Additionally, you can enable saving the current fractional row as sync[0], avoiding calculating the beat in the shader, but also calculating the beat correctly when the beat is modulated.
the send asm code is quite ugly atm (pushf & popf to save stereo flag), but the new regression test should ensure we don't break it again if we eventually refactor it
The working principle is similar as before with x86, but instead of outputting .asm, it outputs .wat. This can be compiled into .wasm by using the wat2wasm assembler.
Play depends on bridge and compile on compiler package. Before, the compiler depended on bridge, but we could not use the compiler to build the library, as the bridge depends on the library. Also, play can now start having slightly more options e.g. wav out etc.
The preprocessing is done sointu-cli and (almost) nothing is done by the NASM preprocessor anymore (some .strucs are still there.
Now, sointu-cli loads the .yml song, defines bunch of macros (go functions / variables) and passes the struct to text/template parses.
This a lot more powerful way to generate .asm code than trying to fight with the nasm preprocessor.
At the moment, tests pass but the repository is a bit of monster, as the library is still compiled using the old approach. Go should
generate the library also from the templates.
The header files are automatically generated during build. No need to #define anything; everything is fixed by the .asm file. This adds go as a dependency to run the unit tests, but this is probably not a bad thing, as go is probably needed anyway if one wants to actually start developing Sointu.
Trying to force a specific song length other than the default never quite worked, so we'll only support the default MAX_SAMPLES & will calculate it for the user in the user in the exported .h header file.
Sointu.asm / lib stuff lives at the root folder. There is a folder called "go4k", which is where
all go stuff lives. Following the ideas from https://medium.com/@benbjohnson/standard-package-layout-7cdbc8391fc1
the go4k folder is the "domain-model" of the go side, and should have no dependencies.
It contains Unit, Instrument, Synth interface etc. Putting go4k under a sub-folder is actually
in the spirit of Ben, as go4k adds dependency to the go language.
Bridge ties the domain-model to the sointulib through cgo. It returns C.Synth, but
makes sure the C.Synth implements the Synth interface, so others are able to use the
Synth no matter how it actually is done. MockSynth and WebProxy synth are good
prospects for other implementations of Synth.
It is a bit fuzzy where methods like "Play" that have no dependencies other than domain
model structs should go. They probably should live in the go4k package as well.
The file-organization on the Go-side is not at all finalized. But how packages are broken
into files is mostly a documentation issue; it does not affect the users of the packages at
all.
BTW: The name go4k was chosen because Ben advocated naming the subpackages
according to the dependency they introduce AND because the prototype of 4klang was
called go4k (there are still some defines in the 4klang source revealing this). go4k thus
honors our roots but is also not so bad name: it's the main package of a 4k synth tracker,
written in go.
test_render_samples_api.c was added to test the api. bridge.go was modified to reflect that there is no need to check for row manually; su_render_samples already returns the information if a row has ended.
The main interface is render_samples function, which renders several samples in one call,
to limit the number of calls from Go to C. This is compiled into a library, which is then
linked and called from bridge.go.
Builds on both 32-bit and 64-bit executables and all tests (except gm.dls stuff obviously, which was excluded) pass on 64-bit Linux. Cannot test the 32-bit executables, as WSL does not support running 32-bit.
The implentation is through a few macros to handle the fact in 64-bit, all addresses have to be loaded first to register and only offsets are ok. Also, push only supports 64-bit registers in 64-bit, so we have _AX, _BX, _CX etc. defines, which are eax, ebx and ecx on 32bit and rax, rbx and rcx on 64bit.
The stereo opcode variants have bit 1 of the command stream set. The polyphony is split into two parts: 1) polyphony, meaning that voices reuse the same opcodes; 2) multitrack voices, meaning that a track triggers more than voice. They both can be flexible defined in any combinations: for example voice 1 and 2 can be triggered by track 1 and use instrument 1, and voice 3 by track 2/instrument 2 and voice 4 by track 3/instrument 2. This is achieved through the use of bitmasks: in the aforementioned example, bit 1 of su_voicetrack_bitmask would be set, meaning "the voice after voice #1 will be triggered by the same track". On the other hand, bits 1 and 3 of su_polyphony_bitmask would be set to indicate that "the voices after #1 and #3 will reuse the same instruments".
