FPGRARS

Fast Pretty Good RISC-V Assembly Rendering System

(name may change at any moment)

FPGRARS is a RISC-V assembly simulator with a graphics display window and keyboard input, similar to RARS, but 200 times faster. If you want to run RISC-V assembly programs easily, learn assembly language, or even build a game, FPGRARS is a great option! (and if it isn't for you please open an issue :)

Running FPGRARS

First, head over to the latest release and download the appropriate executable. Then, you can run a RISC-V assembly file either by running ./fpgrars your_riscv_file.s in a terminal or by dragging the .s onto the executable. If you're on Linux, you might need to chmod +x fpgrars-x86_64-unknown-linux-gnu for FPGRARS to work.

If you have the Rust toolchain installed, you can also download FPGRARS by running cargo install fpgrars.

You may also want to check out Getting Started for a more detailed guide.

Documentation

Still in construction at https://leoriether.github.io/FPGRARS/

Supported ecalls

| Description | a7 | Input | Output | |-------------|----|-------|--------| Print integer | 1 | a0 = integer to print | | Print float | 2 | fa0 = float to print | | Print string | 4 | a0 = address of the string | | Read int | 5 | | a0 = the read integer | Read float | 6 | | fa0 = the read float | Sbrk | 9 | a0 = bytes to allocate (>= 0) | a0 = address of the allocated chunk Exit | 10 | | | Stop execution | 110 | | Print char | 11 | a0 = the char | | Time | 30 | | a0 = low bits of milliseconds since unix epoch, a1 = high bits | Midi out | 31 | a0 = pitch (note), a1 = duration in ms, a2 = instrument (in range 0-127), a3 = volume (also 0-127) | Async sound | Sleep ms | 32 | a0 = number of milliseconds to sleep | | Midi out sync | 33 | a0 = pitch (note), a1 = duration in ms, a2 = instrument (in range 0-127), a3 = volume (also 0-127) | Synchronous sound | Print hex integer | 34 | a0 = integer to print | | Print unsigned integer | 36 | a0 = unsigned integer to print | | Rand seed | 40 | does nothing for now | | Rand int | 41 | | a0 = random integer | Rand int range | 42 | a0 is discarded, a1 = upper bound | a0 = random integer in [0, a1) | Rand float | 43 | | fa0 = random float in [0, 1) | Clear screen | 48 or 148 | a0 = color, a1 = frame | | Open file | 1024 | a0 = address of the null-terminated string for the path, a1 = 0 (read mode), 1 (write mode) or 9 (append mode) | a0 = the file descriptor or -1 if error | Close file | 57 | a0 = a file descriptor | | Seek | 62 | a0 = a file descriptor, a1 = the offset to seek, a2 = 0 (seek from the start of the file), 1 (from the current position) or 2 (from the end) | a0 = the selected position from the start of the file | Read | 63 | a0 = a file descriptor, a1 = address of the buffer, a2 = maximum length to read | a0 = number of bytes read or -1 if error | Write | 64 | a0 = a file descriptor, a1 = address of the buffer, a2 = length to write | a0 = number of bytes written of -1 if error |