add IRQ instructions to AssemblerV1

Author: soypat

rp2-pio/instr.go

@@ -314,16 +314,18 @@ const (
 type IRQIndexMode uint8
 
 const (
+	// Direct: the three LSBs are used directly to index the IRQ flags in this PIO block.
+	IRQDirect IRQIndexMode = 0b00 // direct
 	// Prev: the instruction references an IRQ flag from the next-lower-numbered PIO in the system, wrapping to
 	// the highest-numbered PIO if this is PIO0. Available on RP2350 only.
-	IRQPrev IRQIndexMode = 0b01
+	IRQPrev IRQIndexMode = 0b01 // prev
 	// Rel: the state machine ID (0…3) is added to the IRQ flag index, by way of modulo-4 addition on the two
 	// LSBs. For example, state machine 2 with a flag value of '0x11' will wait on flag 3, and a flag value of '0x13' will
 	// wait on flag 1. This allows multiple state machines running the same program to synchronise with each other.
-	IRQRel IRQIndexMode = 0b10
+	IRQRel IRQIndexMode = 0b10 // rel
 	// Next: the instruction references an IRQ flag from the next-higher-numbered PIO in the system, wrapping to
 	// PIO0 if this is the highest-numbered PIO. Available on RP2350 only.
-	IRQNext IRQIndexMode = 0b11
+	IRQNext IRQIndexMode = 0b11 // next
 )
 
 // EncodeInstr encodes an arbitrary PIO instruction with the given arguments.

rp2-pio/instrv1.go

@@ -81,7 +81,7 @@ func (asm AssemblerV1) MovReverse(dest MovDest, src MovSrc) instructionV0 {
 // MovOSRFromRx reads the selected RX FIFO entry into the OSR. The PIO state machine can read the FIFO entries in any order, indexed
 // either by the Y register, or an immediate Index in the instruction. Requires the SHIFTCTRL_FJOIN_RX_GET configuration field
 // to be set, otherwise its operation is undefined.
-//   - If IdxI (index by immediate) is set, the RX FIFO’s registers are indexed by the two least-significant bits of the Index
+//   - If idxByImmediate (index by immediate) is set, the RX FIFO’s registers are indexed by the two least-significant bits of the Index
 //     operand. Otherwise, they are indexed by the two least-significant bits of the Y register. When IdxI is clear, all non-zero
 //     values of Index are reserved encodings, and their operation is undefined.
 func (asm AssemblerV1) MovOSRFromRx(idxByImmediate bool, RxFifoIndex uint8) instructionV0 {
@@ -106,5 +106,26 @@ func (asm AssemblerV1) Set(dest SetDest, value uint8) instructionV0 {
 	return asm.v0().Set(dest, value)
 }
 
+// IRQSet sets the IRQ flag selected by irqIndex.
+func (asm AssemblerV1) IRQSet(irqIndex uint8, idxMode IRQIndexMode) instructionV0 {
+	return asm.irq(false, false, irqIndex, idxMode)
+}
+
+// IRQClear clears the IRQ flag selected by irqIndex argument. See [AssemblerV1.IRQSet].
+func (asm AssemblerV1) IRQClear(irqIndex uint8, idxMode IRQIndexMode) instructionV0 {
+	return asm.irq(true, false, irqIndex, idxMode)
+}
+
+// IRQWait sets the IRQ flag selected by irqIndex and waits for it to be cleared before proceeding.
+// If Wait is set, Delay cycles do not begin until after the wait period elapses.
+func (asm AssemblerV1) IRQWait(irqIndex uint8, idxMode IRQIndexMode) instructionV0 {
+	return asm.irq(false, true, irqIndex, idxMode)
+}
+
+func (asm AssemblerV1) irq(clear, wait bool, irqIndex uint8, idxMode IRQIndexMode) instructionV0 {
+	instr := _INSTR_BITS_IRQ | uint16(boolAsU8(clear))<<6 | uint16(boolAsU8(wait))<<6 | uint16(idxMode)<<3 | uint16(irqIndex&0b111)
+	return asm.v0().instr(instr)
+}
+
 // Nop instruction unchanged from [AssemblerV0.Nop].
 func (asm AssemblerV1) Nop() instructionV0 { return asm.v0().Nop() }