jpc - Condition jump

jpc     status0, status1, mode, label

Name	Description
status0	Value of status register 0 (the value is either 0 or 1).
status1	Value of status register 1 (the value is either 0 or 1).
mode	Conditional mode (0: OR, 1: AND, 2: Only status register 0, 3: Only status register 1)
label	Label name.

Causes control to jump conditionally based on the status register values.
The value specified by status0 (or status1) is tested for equality against the value of status register 0 (or 1). When mode is 0, the result is true when either status register 0 or status register 1 matches its respective operand.
When mode is 1, both status registers must match their respective operands.
When mode is 2, status register 0 must match status0.
When mode is 3, status register 1 must match status1.
When the specified condition is true, this instruction causes control to jump to the address of the specified label.
Unlike the call instruction, control does not return at a ret instruction. Also, you can specify labels for which ret instructions have not been set.

An error will result if you jump to an external location from within an if or loop block, or jump from an external location into an if or loop block.
An error also will result if you call this instruction immediately prior to an else, endif, endloop, or ret instruction.
Behavior is undefined if you jump to an external location from between the main and endmain labels, or from within subroutines.
In the same way, jumping to a ret instruction within a subroutine also results in undefined behavior.
Jumping to an else, endif, or endloop instruction has the same effect as jumping to the instruction immediately following that instruction.

switch ( mode )
{
    case 0 :
        if ( status0 == Status_register0 || status1 == Status_register1 )
            jump to label
        break;
    case 1 :
        if ( status0 == Status_register0 && status1 == Status_register1 )
            jump to label
        break;
    case 2 :
        if ( status0 == Status_register0 )
            jump to label
        break;
    case 3 :
        if ( status1 == Status_register1 )
            jump to label
        break;
}

jpc     1, 1, 0, subfunction0  // Call subfunction0 if either status register 0 or status register 1 is 1

subfunction0:
..

2011/12/20

Initial version.