// hasExit determines if the given program has at least one
// unconditional EXIT instruction.
func hasExit(bin []cpu.Word) bool {
var op1, op2, a, b cpu.Word
var size int
for i := 0; i < len(bin); i++ {
op1, a, b = cpu.Decode(bin[i])
// Not an EXIT. Skip with next word.
if !(op1 == cpu.EXT && a == cpu.EXIT) {
continue
}
// If the previous instruction is not a branching instruction,
// we have found a non-conditional EXIT.
op2, _, _ = cpu.Decode(bin[i-size])
if op2 < cpu.IFB || op2 > cpu.IFU {
return true
}
// Determine size of instruction.
// Some of them occupy multiple words.
size = 1
if op1 != cpu.EXT && (a == 0x1e || a == 0x1f || (a >= 0x10 && a <= 0x17)) {
size++
}
if b == 0x1e || b == 0x1f || (b >= 0x10 && b <= 0x17) {
size++
}
}
return false
}
// Cost returns the cycle cost for this entry.
func (p *ProfileData) Cost() uint8 {
var c uint8
op, a, b := cpu.Decode(p.Data)
if op == cpu.EXT {
c = opcodes[a]
if b <= 0x1f {
c += operands[b]
}
} else {
c = opcodes[op]
if a <= 0x1f {
c += operands[a]
}
if b <= 0x1f {
c += operands[b]
}
}
return c
}