neon/steps.go

package neon

func stepNOP(c *CPU, addr uint16) Interrupt {
	return NoInterrupt
}

func stepLA_(c *CPU, addr uint16) Interrupt {
	v := c.RAM[addr]
	c.A = v
	return NoInterrupt
}

func stepLAB(c *CPU, addr uint16) Interrupt {
	c.A = c.B
	return NoInterrupt
}

func stepLB_(c *CPU, addr uint16) Interrupt {
	v := c.RAM[addr]
	c.B = v
	return NoInterrupt
}

func stepLBA(c *CPU, addr uint16) Interrupt {
	c.B = c.A
	return NoInterrupt
}

func stepSWP(c *CPU, addr uint16) Interrupt {
	c.A, c.B = c.B, c.A
	return NoInterrupt
}

func stepSTA(c *CPU, addr uint16) Interrupt {
	c.RAM[addr] = c.A
	return NoInterrupt
}

func stepSTB(c *CPU, addr uint16) Interrupt {
	c.RAM[addr] = c.B
	return NoInterrupt
}

func stepAD_(c *CPU, addr uint16) Interrupt {
	v := c.RAM[addr]
	c.A += v
	c.C = c.A < v
	return NoInterrupt
}

func stepADB(c *CPU, addr uint16) Interrupt {
	c.A += c.B
	c.C = c.A < c.B
	return NoInterrupt
}

func stepAC_(c *CPU, addr uint16) Interrupt {
	v := c.RAM[addr]
	c.A += v
	if c.C {
		c.A++
	}
	c.C = c.A < v
	return NoInterrupt
}

func stepACB(c *CPU, addr uint16) Interrupt {
	c.A += c.B
	if c.C {
		c.A++
	}
	c.C = c.A < c.B
	return NoInterrupt
}

func stepINA(c *CPU, addr uint16) Interrupt {
	c.A++
	c.C = c.A == 0
	return NoInterrupt
}

func stepINB(c *CPU, addr uint16) Interrupt {
	c.B++
	c.C = c.B == 0
	return NoInterrupt
}

func stepSB_(c *CPU, addr uint16) Interrupt {
	v := c.RAM[addr]
	c.A -= v
	return NoInterrupt
}

func stepSBB(c *CPU, addr uint16) Interrupt {
	c.A -= c.B
	return NoInterrupt
}

func stepSC_(c *CPU, addr uint16) Interrupt {
	v := c.RAM[addr]
	c.A -= v
	if c.C {
		c.A--
	}
	c.C = c.A > v
	return NoInterrupt
}

func stepSCB(c *CPU, addr uint16) Interrupt {
	c.A -= c.B
	if c.C {
		c.A--
	}
	c.C = c.A > c.B
	return NoInterrupt
}

func stepDEA(c *CPU, addr uint16) Interrupt {
	c.C = c.A == 0
	c.A--
	return NoInterrupt
}

func stepDEB(c *CPU, addr uint16) Interrupt {
	c.C = c.A == 0
	c.B--
	return NoInterrupt
}

func stepTE_(c *CPU, addr uint16) Interrupt {
	v := c.RAM[addr]
	c.T = c.A == v
	return NoInterrupt
}

func stepTEB(c *CPU, addr uint16) Interrupt {
	c.T = c.A == c.B
	return NoInterrupt
}

func stepTG_(c *CPU, addr uint16) Interrupt {
	v := c.RAM[addr]
	c.T = c.A > v
	return NoInterrupt
}

func stepTGB(c *CPU, addr uint16) Interrupt {
	c.T = c.A > c.B
	return NoInterrupt
}

func stepTL_(c *CPU, addr uint16) Interrupt {
	v := c.RAM[addr]
	c.T = c.A < v
	return NoInterrupt
}

func stepTLB(c *CPU, addr uint16) Interrupt {
	c.T = c.A < c.B
	return NoInterrupt
}

func stepTFC(c *CPU, addr uint16) Interrupt {
	c.T = c.C
	return NoInterrupt
}

func stepTFI(c *CPU, addr uint16) Interrupt {
	c.T = c.I
	return NoInterrupt
}

func stepJMP(c *CPU, addr uint16) Interrupt {
	if c.J {
		return NoInterrupt
	}
	v := c.get16(addr)
	c.PC = v
	return NoInterrupt
}

func stepJRF(c *CPU, addr uint16) Interrupt {
	if c.J {
		return NoInterrupt
	}
	v := c.RAM[addr]
	c.PC += uint16(v)
	return NoInterrupt
}

func stepJRB(c *CPU, addr uint16) Interrupt {
	if c.J {
		return NoInterrupt
	}
	v := c.RAM[addr]
	c.PC -= 2 + uint16(v)
	return NoInterrupt
}

func stepJSR(c *CPU, addr uint16) Interrupt {
	if c.J {
		return NoInterrupt // TODO: Does this make sense???
	}
	panic("TODO")
}

func stepRET(c *CPU, addr uint16) Interrupt {
	if c.J {
		return NoInterrupt // TODO: Does this make sense???
	}
	panic("TODO")
}

func stepSET(c *CPU, addr uint16) Interrupt {
	c.T = true
	return NoInterrupt
}

func stepSEC(c *CPU, addr uint16) Interrupt {
	c.C = true
	return NoInterrupt
}

func stepSEI(c *CPU, addr uint16) Interrupt {
	c.I = true
	return NoInterrupt
}

func stepSEJ(c *CPU, addr uint16) Interrupt {
	c.J = true
	return NoInterrupt
}

func stepCLT(c *CPU, addr uint16) Interrupt {
	c.T = false
	return NoInterrupt
}

func stepCLC(c *CPU, addr uint16) Interrupt {
	c.C = false
	return NoInterrupt
}

func stepCLI(c *CPU, addr uint16) Interrupt {
	c.I = false
	return NoInterrupt
}

func stepCLJ(c *CPU, addr uint16) Interrupt {
	c.J = false
	return NoInterrupt
}

func stepINT(c *CPU, addr uint16) Interrupt {
	if c.I {
		return NoInterrupt
	}
	v := c.RAM[addr]
	return Interrupt(v)
}