Console IO

These calls use the console IPR registers to perform IO to the MacVAXC I0 Window.They provide a simple method of performing character IO without needing to write a device driver.

XFC #READCHAR (0)

Reads one character from keyboard with no echoing. The character is returned in the low byte of r0.

XFC #WRITECHAR (1)

Output one character to the I/O window. The character is passed in the low byte of r0.

XFC #READLINE (2)

Inputs one line from the keyboard (equivalent to Pascal's readln). Characters are echoed and erase/kill processing is performed. On execution, r0 must contain the address where the string is to be placed. After execution r0 points to one byte after the end of the string, and r1 contains the length of the string. An end of line character is not appended to the return string.

XFC #WRITESTRING (3)

Output one line to the screen (equivalent to Pascal's write). On execution, r0 must contain the address of a buffer which contains the string to output, and r1 the length of the string. Characters from the buffer are output one at a time until a null byte is reached or r1 characters have been written. After execution r0 points to the byte after the terminating character of the string.