sprites!!!!!!

1 files changed, 80 insertions, 0 deletions

diff --git a/cpu/instructions.go b/cpu/instructions.go
index b74a2db..b4d4bbe 100644
--- a/cpu/instructions.go
+++ b/cpu/instructions.go
@@ -226,3 +226,83 @@ func jamExec(c *CPU, op operand) {
 	c.Jammed = true
 	c.PC--
 }
+
+// and with immediate, then carry takes the sign bit
+func ancExec(c *CPU, op operand) {
+	c.A &= c.operandValue(op)
+	c.setZN(c.A)
+	c.setFlag(FlagC, c.A&0x80 != 0)
+}
+
+// and with immediate, then lsr a
+func alrExec(c *CPU, op operand) {
+	v := c.A & c.operandValue(op)
+	c.setFlag(FlagC, v&0x01 != 0)
+	c.A = v >> 1
+	c.setZN(c.A)
+}
+
+// and with immediate, then ror a, but C and V come from bits 6 and 5 of the
+// result (binary mode only, the 2A03 has no decimal mode)
+func arrExec(c *CPU, op operand) {
+	v := c.A & c.operandValue(op)
+	var carryIn uint8
+	if c.flag(FlagC) {
+		carryIn = 0x80
+	}
+	c.A = v>>1 | carryIn
+	c.setZN(c.A)
+	c.setFlag(FlagC, c.A&0x40 != 0)
+	c.setFlag(FlagV, (c.A>>6^c.A>>5)&0x01 != 0)
+}
+
+// x = (a & x) - immediate, like cmp: no borrow in, V untouched
+func axsExec(c *CPU, op operand) {
+	v := c.A & c.X
+	imm := c.operandValue(op)
+	c.setFlag(FlagC, v >= imm)
+	c.X = v - imm
+	c.setZN(c.X)
+}
+
+// memory & sp goes into a, x and sp
+func lasExec(c *CPU, op operand) {
+	v := c.operandValue(op) & c.SP
+	c.A, c.X, c.SP = v, v, v
+	c.setZN(v)
+}
+
+const unstableMagic uint8 = 0xEE
+
+func aneExec(c *CPU, op operand) {
+	c.A = (c.A | unstableMagic) & c.X & c.operandValue(op)
+	c.setZN(c.A)
+}
+
+func lxaExec(c *CPU, op operand) {
+	c.A = (c.A | unstableMagic) & c.operandValue(op)
+	c.X = c.A
+	c.setZN(c.A)
+}
+
+func (c *CPU) storeHighAnd(op operand, v uint8) {
+	baseHi := uint8(op.addr >> 8)
+	if op.pageCrossed {
+		baseHi--
+	}
+	v &= baseHi + 1
+	addr := op.addr
+	if op.pageCrossed {
+		addr = uint16(v)<<8 | addr&0x00FF
+	}
+	c.write(addr, v)
+}
+
+func ahxExec(c *CPU, op operand) { c.storeHighAnd(op, c.A&c.X) }
+func shxExec(c *CPU, op operand) { c.storeHighAnd(op, c.X) }
+func shyExec(c *CPU, op operand) { c.storeHighAnd(op, c.Y) }
+
+func tasExec(c *CPU, op operand) {
+	c.SP = c.A & c.X
+	c.storeHighAnd(op, c.SP)
+}