Section A.2 OS Calls
Calling the operating system is done by the
syscall instruction. The operation to be carried out is specified by the $v0 register. Potential arguments to the system call are passed in the argument registers.| Action | $v0 |
Description |
| print integer | 1 |
$a0 = number to be printed. |
| print string | 4 |
$a0 = address of ASCIIZ string. |
| read integer | 5 | Read number stored in $v0. |
| read string | 8 | $a0 = start address of memory area where characters are put. $a1 = maximum number of characters to read. |
| exit | 10 | End program execution. |
| print character | 11 |
$a0 = ASCII code of character to print. |
| read character | 12 | ASCII code of read character stored in $v0. |
