Service
 System Call Code
 Arguments
 Result
PRINT_INT
 1
 $a0=int
PRINT_FLOAT
 2
 $f12=float
PRINT_DOUBLE
 3
 $f12=double
PRINT_STRING
 4
 $a0=string
READ_INT
 5
integer in $v0
READ_FLOAT
 6
float in $f0
READ_DOUBLE
 7
double in $f0
READ_STRING
 8
 $a0=buffer, $a1=length
SBRK
 9
 $a0=amount
 address in $v0 of newly allocated memory
EXIT
 10
Terminate Program
PRINT_CHARACTER
 11
 $a0=character
READ_CHARACTER
 12
character in $v0
FILE_OPEN
 13
 $a0=string (path and file name), $a1=flags, $a2=permission mode
a1 = any of the following:
Read Only = 0x0
Write Only=0x1
Read/Write=0x2
which may be bit-wise or'd with the creation options:
Create=0x8 unix, 0x100 windows
Truncate=0x200 unix, 0x200 windows
Append=0x2000 unix, 0x8 windows
on windows, the "file type" may be specified:
Text=0x4000
Binary=0x8000
a2= read/write permissions (Bitwise or for both)
Read=0x100
Write=0x80
 results in $v0
-1 = Error
Anything else is a file descriptor (to use the file in the future)
FILE_READ
 14
 $a0=file descriptor (to an open/good file)
$a1=buffer
$a2=amount to read
 Data read from file into buffer.
result in $v0
-1=Error
0=End of File (With no bytes read)
>0 = The number of bytes read (which will be < or == amount)
FILE_WRITE
 15
 $a0=file descriptor (to an open/good file)
$a1=buffer
$a2=amount to write
 Data written from the buffer into the file.
result in $v0
-1=Error
0=End of File (With no bytes read)
>0 = The number of bytes written (which will be < or == amount)
FILE_CLOSE
 16
 $a0=file descriptor (to an open/good file)
 The file is closed (the descriptor will no longer be valid)