switch.8o

# switch/case macro, should be followed by a jump table with the same number of entries as cases
:macro switch REG {
	v0 := REG
	v0 <<= v0
	:calc table { HERE + 10 }
	# for Super-CHIP compatibility, we also load VX for use with jump0 where X is the upper digit of the table's address
	# note that if the table is located at address 0xA00 or above, we'll clobber necessary registers here!
	:calc table-reg { table >> 8 }
	v9 := 0x9
	v9 -= v0
	if vf == 0 then
		:breakpoint switch-uses-reserved-registers
	:byte { 0x80 | table-reg } 0x00 # 8X00, VX := V0
	jump0 table
}