FPGRARS aims to provide a RISC-V assembly simulator with 8-bit color graphics display and keyboard input, similar to RARS, but faster.
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.
| Description | a7 | Input | Output |
|---|---|---|---|
| Print integer | 1 | a0 = integer to print | |
| Print string | 4 | a0 = address of the string | |
| Read int | 5 | a0 = the read integer | |
| Print float | 6 | a0 = float to print | |
| 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 | does nothing for now | |
| Sleep ms | 32 | a0 = number of milliseconds to sleep | |
| Midi out sync | 33 | does nothing for now | |
| 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 |