URL
https://dpetersanderson.github.io/Help/SyscallHelp.html
Table
| Service | Code in $v0 | Arguments | Result |
|---|---|---|---|
| print integer | 1 | $a0 = integer to print | |
| print float | 2 | $f12 = float to print | |
| print double | 3 | $f12 = double to print | |
| print string | 4 | $a0 = address of null-terminated string to print | |
| read integer | 5 | $v0 contains integer read | |
| read float | 6 | $f0 contains float read | |
| read double | 7 | $f0 contains double read | |
| read string | 8 | a1 = maximum number of characters to read | See note below table |
| sbrk (allocate heap memory) | 9 | $a0 = number of bytes to allocate | $v0 contains address of allocated memory |
| exit (terminate execution) | 10 | ||
| print character | 11 | $a0 = character to print | See note below table |
| read character | 12 | $v0 contains character read | |
| open file | 13 | a1 = flags $a2 = mode | $v0 contains file descriptor (negative if error). See note below table |
| read from file | 14 | a1 = address of input buffer $a2 = maximum number of characters to read | $v0 contains number of characters read (0 if end-of-file, negative if error). See note below table |
| write to file | 15 | a1 = address of output buffer $a2 = number of characters to write | $v0 contains number of characters written (negative if error). See note below table |
| close file | 16 | $a0 = file descriptor | |
| exit2 (terminate with value) | 17 | $a0 = termination result | See note below table |
| Services 1 through 17 are compatible with the SPIM simulator, other than Open File (13) as described in the Notes below the table. Services 30 and higher are exclusive to MARS. | |||
| time (system time) | 30 | a1 = high order 32 bits of system time. See note below table | |
| MIDI out | 31 | a1 = duration in milliseconds a3 = volume (0-127) | Generate tone and return immediately. See note below table |
| sleep | 32 | $a0 = the length of time to sleep in milliseconds. | Causes the MARS Java thread to sleep for (at least) the specified number of milliseconds. This timing will not be precise, as the Java implementation will add some overhead. |
| MIDI out synchronous | 33 | a1 = duration in milliseconds a3 = volume (0-127) | Generate tone and return upon tone completion. See note below table |
| print integer in hexadecimal | 34 | $a0 = integer to print | Displayed value is 8 hexadecimal digits, left-padding with zeroes if necessary. |
| print integer in binary | 35 | $a0 = integer to print | Displayed value is 32 bits, left-padding with zeroes if necessary. |
| print integer as unsigned | 36 | $a0 = integer to print | Displayed as unsigned decimal value. |
| (not used) | 37-39 | ||
| set seed | 40 | a1 = seed for corresponding pseudorandom number generator. | No values are returned. Sets the seed of the corresponding underlying Java pseudorandom number generator (java.util.Random). See note below table |
| random int | 41 | $a0 = i.d. of pseudorandom number generator (any int). | $a0 contains the next pseudorandom, uniformly distributed int value from this random number generator’s sequence. See note below table |
| random int range | 42 | a1 = upper bound of range of returned values. | $a0 contains pseudorandom, uniformly distributed int value in the range 0 ⇐ [int] < [upper bound], drawn from this random number generator’s sequence. See note below table |
| random float | 43 | $a0 = i.d. of pseudorandom number generator (any int). | $f0 contains the next pseudorandom, uniformly distributed float value in the range 0.0 ⇐ f < 1.0 from this random number generator’s sequence. See note below table |