Jump

Jump is a three-decle opcode that is represented as one of several different possible mnemonics, depending on the flags indicated in the second byte of the opcode. The opcode breaks down as follows.

   Format - Decle #1     Format - Decle #2     Format - Decle #3
   0000:0000:0000:0100  0000:00rr:aaaa:aaff  0000:00aa:aaaa:aaaa

   where:

       rr    indicates the register into which to store the return address
             such that:
                 rr == 00    indicates to store return address in register R4
                 rr == 01    indicates register R5
                 rr == 10    indicates register R6
                 rr == 11    indicates that the CP1610 should not store the 
                             return address, signaling a Jump without return

       ff    indicates how to affect the Interrupt (I) flag in the CP1610
             such that:
                 ff == 00    indicates not to affect the Interrupt flag
                 ff == 01    indicates to set the Interrupt flag
                 ff == 10    indicates to clear the Interrupt flag
                 ff == 11    unknown opcode (behavior unknown!!)

       aaaaaaaaaaaaaaaa    indicates the address to where the CP1610 should Jump

This opcode is often represented as many different mnemonics, to make life a little easier for the programmer. The mnemonic used depends on the combination of the rr and ff parameters mentioned above, according to the following chart.

	rr == 00	rr == 01	rr == 10	rr == 11
ff == 00	JSR R4, $aaaa	JSR R5, $aaaa	JSR R6, $aaaa	J $aaaa
ff == 01	JSRE R4, $aaaa	JSRE R5, $aaaa	JSRE R6, $aaaa	JE $aaaa
ff == 10	JSRD R4, $aaaa	JSRD R5, $aaaa	JSRD R6, $aaaa	JD $aaaa
ff == 11	invalid opcodes