Current sources
BUILD: $ ./sim.sh #run compiled $ ./compile.sh #run pipelineC $ ./verilator.sh #run verilator simulation $ ./gen.sh #run compiled after C to C translation $ ./synth.sh #run synthesis
UPDATE SOURCES / CODE GENERATOR:
Victor's review (from diff): -double constants (0 -> 0.0) -add casts after <<, >> -int -> int32_t / int16_t -Material -> material_t -no return on the middle (plane_has_hole)
- ~0x7FF -> ~(int16_t)0x7FF) -init plane_center_start in reset_state -ray_plane_intersect: define all variables in outmost scope -render_pixel_internal: split cx, cy calc in two operations -render_pixel: change saturation logic: pix.r = (r >= 256) ? 255 : (uint8_t)r; -next_state_fun, won logic: if((n.stinout.score >= 15000) & (n.stinout.won==0)) -reset_state: int startpos -> int16_t -use macros for the colors, so can be multiplied by constants -change 1e23 to 1.0e23
Julian's review:
- Integer inputs to bit shift left functions should be cast to full 32b. x = (int32_t)1 << y; (pipelinec has no default int literal size)
- No bool type, no bool operators, use bitwise with extra parenthesis. https://github.com/JulianKemmerer/PipelineC/issues/24 -Typedef issues:
- https://github.com/JulianKemmerer/PipelineC/issues/52
- Cant use typedef to just rename a type (only can use for enums and structs) (use #define to 'rename' types for now)
- Structs must use a struct alias name matching the struct name (so no 'struct' keyword outside of def).
- Dont use types and variables with the same case-insensitive name (ex. change 'Material' type to material_t so use in code is
material_t material). VHDL case insensitivity issues. - Dont support constructor syntax, cast, etc instead. Ex cant. float f = float(0.0);
- Removed redundant casts: https://github.com/JulianKemmerer/PipelineC/issues/53
- No support for complex compile time calculations
- Ex. const object_coord_t plane_center_start = fixed3_make(...); // Requires computing fixed3_make by the compiler
- Can move decl inside function where used. Will be resolved like other constant wires by synthesis 'at run time'
- Use of PipelineC bit manip funcs, ex. float_to_uint is float_31_0
- No support for 'double' type like there is for float
- Use width specified int 'int32_t' instead of int
- Init floats with float consts, BIG_FLOAT = 1e23 is technically an int larger than VHDL can support, 1.0e23 is a float, is fine
- Cast or specify mixed int+float operations , ex. if(diff > 0) where diff is float needs to be if(diff > 0.0) or if(diff > (float)0)
- Function names can't start with underscore (VHDL naming rules)
- No support for unions (cant have members .x,y,z and .r,g,b for same struct)
- Minor things commented out like bool, FRAME_WIDTH, pixel, etc defined elsewhere
Current pending tasks
VICTOR 0) DONE: Reproduce Julian's test results (verilator)
- tweak the code or generator to avoid any need of manual changes of generated code (see Julian's review and Victor's review above)
- Integrate game logic
- Integrate the already developed fixed point optimizations
- Check if floor reflections are enabled -- seems they don't
- Try to add antialiasing - check highest resolution achievable
- test the rendering code on a GPU (may get full resolution at realtime)
- test cflextypes to compare estimated vs. used resources & effect of changing mantissa precision
JULIAN
- do a full pipelining, including pipelined mults for ECP5 if needed
- check possible fmax (thus resolution) -- currently 136MHz without pipelining (just fp mult test)
POSSIBLE FEATURES
-Activate grayscale rendering -Activate subpixel offsets -Use a 7" LCD screen (800x480) and show both a monitor and a LCD working
SELLING POINTS
-fully open source toolchain & example board
Getting ECP5 85F device synthesizing
Install tools: see apio (ecp5)
$ ./src/pipelinec ./examples/raytracer_fixed/pipelinec_app.c --out_dir ./examples/raytracer_fixed/build --comb --sim --verilator #only --comb for resource estimates
FUTURE IMPROVEMENTS
-use internal adders in DSP slices (ECP5 as a start) for fmadd operations
TOOLS
GHDL 2.0.0-dev (1.0.0.r836.g260be4a7.dirty) [Dunoon edition] https://github.com/ghdl/ghdl Building: https://ghdl.github.io/ghdl/development/building/index.html
Mine: GHDL 2.0.0-dev (1.0.0.r1015.g3a3e2f01) [Dunoon edition] Compiled with GNAT Version: 8.3.0 mcode code generator
Yosys 0.10+30 (git sha1 a15b01a77, clang 10.0.0-4ubuntu1 -fPIC -Os) Mine: Yosys 0.9+4303 (git sha1 c88eaea6, clang 7.0.1-8+deb10u2 -fPIC -Os)
Verilator 4.215 devel rev v4.214-2-g0ef9087f