src/rp2_common/hardware_pio/include/hardware/pio_instructions.h

/*
 * Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#ifndef _HARDWARE_PIO_INSTRUCTIONS_H_
#define _HARDWARE_PIO_INSTRUCTIONS_H_

#include "pico.h"

/** \brief PIO instruction encoding 
 *  \defgroup pio_instructions pio_instructions
 *  \ingroup hardware_pio
 * 
 * Functions for generating PIO instruction encodings programmatically. In debug builds
 *`PARAM_ASSERTIONS_ENABLED_PIO_INSTRUCTIONS` can be set to 1 to enable validation of encoding function
 * parameters.
 *
 * For fuller descriptions of the instructions in question see the "RP2040 Datasheet"
 */

// PICO_CONFIG: PARAM_ASSERTIONS_ENABLED_PIO_INSTRUCTIONS, Enable/disable assertions in the PIO instructions, type=bool, default=0, group=pio_instructions
#ifndef PARAM_ASSERTIONS_ENABLED_PIO_INSTRUCTIONS
#define PARAM_ASSERTIONS_ENABLED_PIO_INSTRUCTIONS 0
#endif

#ifdef __cplusplus
extern "C" {
#endif

enum pio_instr_bits {
    pio_instr_bits_jmp = 0x0000,
    pio_instr_bits_wait = 0x2000,
    pio_instr_bits_in = 0x4000,
    pio_instr_bits_out = 0x6000,
    pio_instr_bits_push = 0x8000,
    pio_instr_bits_pull = 0x8080,
    pio_instr_bits_mov = 0xa000,
    pio_instr_bits_irq = 0xc000,
    pio_instr_bits_set = 0xe000,
};

#ifndef NDEBUG
#define _PIO_INVALID_IN_SRC    0x08u
#define _PIO_INVALID_OUT_DEST 0x10u
#define _PIO_INVALID_SET_DEST 0x20u
#define _PIO_INVALID_MOV_SRC  0x40u
#define _PIO_INVALID_MOV_DEST 0x80u
#else
#define _PIO_INVALID_IN_SRC    0u
#define _PIO_INVALID_OUT_DEST 0u
#define _PIO_INVALID_SET_DEST 0u
#define _PIO_INVALID_MOV_SRC  0u
#define _PIO_INVALID_MOV_DEST 0u
#endif

/*! \brief Enumeration of values to pass for source/destination args for instruction encoding functions
 *  \ingroup pio_instructions
 *
 * \note Not all values are suitable for all functions. Validity is only checked in debug mode when
 * `PARAM_ASSERTIONS_ENABLED_PIO_INSTRUCTIONS` is 1
 */
enum pio_src_dest {
    pio_pins = 0u,
    pio_x = 1u,
    pio_y = 2u,
    pio_null = 3u | _PIO_INVALID_SET_DEST | _PIO_INVALID_MOV_DEST,
    pio_pindirs = 4u | _PIO_INVALID_IN_SRC | _PIO_INVALID_MOV_SRC | _PIO_INVALID_MOV_DEST,
    pio_exec_mov = 4u | _PIO_INVALID_IN_SRC | _PIO_INVALID_OUT_DEST | _PIO_INVALID_SET_DEST | _PIO_INVALID_MOV_SRC,
    pio_status = 5u | _PIO_INVALID_IN_SRC | _PIO_INVALID_OUT_DEST | _PIO_INVALID_SET_DEST | _PIO_INVALID_MOV_DEST,
    pio_pc = 5u | _PIO_INVALID_IN_SRC | _PIO_INVALID_SET_DEST | _PIO_INVALID_MOV_SRC,
    pio_isr = 6u | _PIO_INVALID_SET_DEST,
    pio_osr = 7u | _PIO_INVALID_OUT_DEST | _PIO_INVALID_SET_DEST,
    pio_exec_out = 7u | _PIO_INVALID_IN_SRC | _PIO_INVALID_SET_DEST | _PIO_INVALID_MOV_SRC | _PIO_INVALID_MOV_DEST,
};

static inline uint _pio_major_instr_bits(uint instr) {
    return instr & 0xe000u;
}

static inline uint _pio_encode_instr_and_args(enum pio_instr_bits instr_bits, uint arg1, uint arg2) {
    valid_params_if(PIO_INSTRUCTIONS, arg1 <= 0x7);
#if PARAM_ASSERTIONS_ENABLED(PIO_INSTRUCTIONS)
    uint32_t major = _pio_major_instr_bits(instr_bits);
    if (major == pio_instr_bits_in || major == pio_instr_bits_out) {
        assert(arg2 && arg2 <= 32);
    } else {
        assert(arg2 <= 31);
    }
#endif
    return instr_bits | (arg1 << 5u) | (arg2 & 0x1fu);
}

static inline uint _pio_encode_instr_and_src_dest(enum pio_instr_bits instr_bits, enum pio_src_dest dest, uint value) {
    return _pio_encode_instr_and_args(instr_bits, dest & 7u, value);
}

/*! \brief Encode just the delay slot bits of an instruction
 *  \ingroup pio_instructions
 *
 * \note This function does not return a valid instruction encoding; instead it returns an encoding of the delay
 * slot suitable for `OR`ing with the result of an encoding function for an actual instruction. Care should be taken when
 * combining the results of this function with the results of \ref pio_encode_sideset and \ref pio_encode_sideset_opt
 * as they share the same bits within the instruction encoding.
 *
 * \param cycles the number of cycles 0-31 (or less if side set is being used)
 * \return the delay slot bits to be ORed with an instruction encoding
 */
static inline uint pio_encode_delay(uint cycles) {
    // note that the maximum cycles will be smaller if sideset_bit_count > 0
    valid_params_if(PIO_INSTRUCTIONS, cycles <= 0x1f);
    return cycles << 8u;
}

/*! \brief Encode just the side set bits of an instruction (in non optional side set mode)
 *  \ingroup pio_instructions
 *
 * \note This function does not return a valid instruction encoding; instead it returns an encoding of the side set bits
 * suitable for `OR`ing with the result of an encoding function for an actual instruction. Care should be taken when
 * combining the results of this function with the results of \ref pio_encode_delay as they share the same bits
 * within the instruction encoding.
 *
 * \param sideset_bit_count number of side set bits as would be specified via `.sideset` in pioasm
 * \param value the value to sideset on the pins
 * \return the side set bits to be ORed with an instruction encoding
 */
static inline uint pio_encode_sideset(uint sideset_bit_count, uint value) {
    valid_params_if(PIO_INSTRUCTIONS, sideset_bit_count >= 1 && sideset_bit_count <= 5);
    valid_params_if(PIO_INSTRUCTIONS, value <= ((1u << sideset_bit_count) - 1));
    return value << (13u - sideset_bit_count);
}

/*! \brief Encode just the side set bits of an instruction (in optional -`opt` side set mode)
 *  \ingroup pio_instructions
 *
 * \note This function does not return a valid instruction encoding; instead it returns an encoding of the side set bits
 * suitable for `OR`ing with the result of an encoding function for an actual instruction. Care should be taken when
 * combining the results of this function with the results of \ref pio_encode_delay as they share the same bits
 * within the instruction encoding.
 *
 * \param sideset_bit_count number of side set bits as would be specified via `.sideset <n> opt` in pioasm
 * \param value the value to sideset on the pins
 * \return the side set bits to be ORed with an instruction encoding
 */
static inline uint pio_encode_sideset_opt(uint sideset_bit_count, uint value) {
    valid_params_if(PIO_INSTRUCTIONS, sideset_bit_count >= 1 && sideset_bit_count <= 4);
    valid_params_if(PIO_INSTRUCTIONS, value <= ((1u << sideset_bit_count) - 1));
    return 0x1000u | value << (12u - sideset_bit_count);
}

/*! \brief Encode an unconditional JMP instruction
 *  \ingroup pio_instructions
 *
 * This is the equivalent of `JMP <addr>`
 *
 * \param addr The target address 0-31 (an absolute address within the PIO instruction memory)
 * \return The instruction encoding with 0 delay and no side set value
 * \see pio_encode_delay, pio_encode_sideset, pio_encode_sideset_opt
 */
static inline uint pio_encode_jmp(uint addr) {
    return _pio_encode_instr_and_args(pio_instr_bits_jmp, 0, addr);
}

/*! \brief Encode a conditional JMP if scratch X zero instruction
 *  \ingroup pio_instructions
 *
 * This is the equivalent of `JMP !X <addr>`
 *
 * \param addr The target address 0-31 (an absolute address within the PIO instruction memory)
 * \return The instruction encoding with 0 delay and no side set value
 * \see pio_encode_delay, pio_encode_sideset, pio_encode_sideset_opt
 */
static inline uint pio_encode_jmp_not_x(uint addr) {
    return _pio_encode_instr_and_args(pio_instr_bits_jmp, 1, addr);
}

/*! \brief Encode a conditional JMP if scratch X non-zero (and post-decrement X) instruction
 *  \ingroup pio_instructions
 *
 * This is the equivalent of `JMP X-- <addr>`
 *
 * \param addr The target address 0-31 (an absolute address within the PIO instruction memory)
 * \return The instruction encoding with 0 delay and no side set value
 * \see pio_encode_delay, pio_encode_sideset, pio_encode_sideset_opt
 */
static inline uint pio_encode_jmp_x_dec(uint addr) {
    return _pio_encode_instr_and_args(pio_instr_bits_jmp, 2, addr);
}

/*! \brief Encode a conditional JMP if scratch Y zero instruction
 *  \ingroup pio_instructions
 *
 * This is the equivalent of `JMP !Y <addr>`
 *
 * \param addr The target address 0-31 (an absolute address within the PIO instruction memory)
 * \return The instruction encoding with 0 delay and no side set value
 * \see pio_encode_delay, pio_encode_sideset, pio_encode_sideset_opt
 */
static inline uint pio_encode_jmp_not_y(uint addr) {
    return _pio_encode_instr_and_args(pio_instr_bits_jmp, 3, addr);
}

/*! \brief Encode a conditional JMP if scratch Y non-zero (and post-decrement Y) instruction
 *  \ingroup pio_instructions
 *
 * This is the equivalent of `JMP Y-- <addr>`
 *
 * \param addr The target address 0-31 (an absolute address within the PIO instruction memory)
 * \return The instruction encoding with 0 delay and no side set value
 * \see pio_encode_delay, pio_encode_sideset, pio_encode_sideset_opt
 */
static inline uint pio_encode_jmp_y_dec(uint addr) {
    return _pio_encode_instr_and_args(pio_instr_bits_jmp, 4, addr);
}

/*! \brief Encode a conditional JMP if scratch X not equal scratch Y instruction
 *  \ingroup pio_instructions
 *
 * This is the equivalent of `JMP X!=Y <addr>`
 *
 * \param addr The target address 0-31 (an absolute address within the PIO instruction memory)
 * \return The instruction encoding with 0 delay and no side set value
 * \see pio_encode_delay, pio_encode_sideset, pio_encode_sideset_opt
 */
static inline uint pio_encode_jmp_x_ne_y(uint addr) {
    return _pio_encode_instr_and_args(pio_instr_bits_jmp, 5, addr);
}

/*! \brief Encode a conditional JMP if input pin high instruction
 *  \ingroup pio_instructions
 *
 * This is the equivalent of `JMP PIN <addr>`
 *
 * \param addr The target address 0-31 (an absolute address within the PIO instruction memory)
 * \return The instruction encoding with 0 delay and no side set value
 * \see pio_encode_delay, pio_encode_sideset, pio_encode_sideset_opt
 */
static inline uint pio_encode_jmp_pin(uint addr) {
    return _pio_encode_instr_and_args(pio_instr_bits_jmp, 6, addr);
}

/*! \brief Encode a conditional JMP if output shift register not empty instruction
 *  \ingroup pio_instructions
 *
 * This is the equivalent of `JMP !OSRE <addr>`
 *
 * \param addr The target address 0-31 (an absolute address within the PIO instruction memory)
 * \return The instruction encoding with 0 delay and no side set value
 * \see pio_encode_delay, pio_encode_sideset, pio_encode_sideset_opt
 */
static inline uint pio_encode_jmp_not_osre(uint addr) {
    return _pio_encode_instr_and_args(pio_instr_bits_jmp, 7, addr);
}

static inline uint _pio_encode_irq(bool relative, uint irq) {
    valid_params_if(PIO_INSTRUCTIONS, irq <= 7);
    return (relative ? 0x10u : 0x0u) | irq;
}

/*! \brief Encode a WAIT for GPIO pin instruction
 *  \ingroup pio_instructions
 *
 * This is the equivalent of `WAIT <polarity> GPIO <gpio>`
 *
 * \param polarity true for `WAIT 1`, false for `WAIT 0`
 * \param gpio The real GPIO number 0-31
 * \return The instruction encoding with 0 delay and no side set value
 * \see pio_encode_delay, pio_encode_sideset, pio_encode_sideset_opt
 */
static inline uint pio_encode_wait_gpio(bool polarity, uint gpio) {
    return _pio_encode_instr_and_args(pio_instr_bits_wait, 0u | (polarity ? 4u : 0u), gpio);
}

/*! \brief Encode a WAIT for pin instruction
 *  \ingroup pio_instructions
 *
 * This is the equivalent of `WAIT <polarity> PIN <pin>`
 *
 * \param polarity true for `WAIT 1`, false for `WAIT 0`
 * \param pin The pin number 0-31 relative to the executing SM's input pin mapping
 * \return The instruction encoding with 0 delay and no side set value
 * \see pio_encode_delay, pio_encode_sideset, pio_encode_sideset_opt
 */
static inline uint pio_encode_wait_pin(bool polarity, uint pin) {
    return _pio_encode_instr_and_args(pio_instr_bits_wait, 1u | (polarity ? 4u : 0u), pin);
}

/*! \brief Encode a WAIT for IRQ instruction
 *  \ingroup pio_instructions
 *
 * This is the equivalent of `WAIT <polarity> IRQ <irq> <relative>`
 *
 * \param polarity true for `WAIT 1`, false for `WAIT 0`
 * \param relative true for a `WAIT IRQ <irq> REL`, false for regular `WAIT IRQ <irq>`
 * \param irq the irq number 0-7
 * \return The instruction encoding with 0 delay and no side set value
 * \see pio_encode_delay, pio_encode_sideset, pio_encode_sideset_opt
 */
static inline uint pio_encode_wait_irq(bool polarity, bool relative, uint irq) {
    valid_params_if(PIO_INSTRUCTIONS, irq <= 7);
    return _pio_encode_instr_and_args(pio_instr_bits_wait, 2u | (polarity ? 4u : 0u), _pio_encode_irq(relative, irq));
}

/*! \brief Encode an IN instruction
 *  \ingroup pio_instructions
 *
 * This is the equivalent of `IN <src>, <count>`
 *
 * \param src The source to take data from
 * \param count The number of bits 1-32
 * \return The instruction encoding with 0 delay and no side set value
 * \see pio_encode_delay, pio_encode_sideset, pio_encode_sideset_opt
 */
static inline uint pio_encode_in(enum pio_src_dest src, uint count) {
    valid_params_if(PIO_INSTRUCTIONS, !(src & _PIO_INVALID_IN_SRC));
    return _pio_encode_instr_and_src_dest(pio_instr_bits_in, src, count);
}

/*! \brief Encode an OUT instruction
 *  \ingroup pio_instructions
 *
 * This is the equivalent of `OUT <src>, <count>`
 *
 * \param dest The destination to write data to
 * \param count The number of bits 1-32
 * \return The instruction encoding with 0 delay and no side set value
 * \see pio_encode_delay, pio_encode_sideset, pio_encode_sideset_opt
 */
static inline uint pio_encode_out(enum pio_src_dest dest, uint count) {
    valid_params_if(PIO_INSTRUCTIONS, !(dest & _PIO_INVALID_OUT_DEST));
    return _pio_encode_instr_and_src_dest(pio_instr_bits_out, dest, count);
}

/*! \brief Encode a PUSH instruction
 *  \ingroup pio_instructions
 *
 * This is the equivalent of `PUSH <if_full>, <block>`
 *
 * \param if_full true for `PUSH IF_FULL ...`, false for `PUSH ...`
 * \param block true for `PUSH ... BLOCK`, false for `PUSH ...`
 * \return The instruction encoding with 0 delay and no side set value
 * \see pio_encode_delay, pio_encode_sideset, pio_encode_sideset_opt
 */
static inline uint pio_encode_push(bool if_full, bool block) {
    return _pio_encode_instr_and_args(pio_instr_bits_push, (if_full ? 2u : 0u) | (block ? 1u : 0u), 0);
}

/*! \brief Encode a PULL instruction
 *  \ingroup pio_instructions
 *
 * This is the equivalent of `PULL <if_empty>, <block>`
 *
 * \param if_empty true for `PULL IF_EMPTY ...`, false for `PULL ...`
 * \param block true for `PULL ... BLOCK`, false for `PULL ...`
 * \return The instruction encoding with 0 delay and no side set value
 * \see pio_encode_delay, pio_encode_sideset, pio_encode_sideset_opt
 */
static inline uint pio_encode_pull(bool if_empty, bool block) {
    return _pio_encode_instr_and_args(pio_instr_bits_pull, (if_empty ? 2u : 0u) | (block ? 1u : 0u), 0);
}

/*! \brief Encode a MOV instruction
 *  \ingroup pio_instructions
 *
 * This is the equivalent of `MOV <dest>, <src>`
 *
 * \param dest The destination to write data to
 * \param src The source to take data from
 * \return The instruction encoding with 0 delay and no side set value
 * \see pio_encode_delay, pio_encode_sideset, pio_encode_sideset_opt
 */
static inline uint pio_encode_mov(enum pio_src_dest dest, enum pio_src_dest src) {
    valid_params_if(PIO_INSTRUCTIONS, !(dest & _PIO_INVALID_MOV_DEST));
    valid_params_if(PIO_INSTRUCTIONS, !(src & _PIO_INVALID_MOV_SRC));
    return _pio_encode_instr_and_src_dest(pio_instr_bits_mov, dest, src & 7u);
}

/*! \brief Encode a MOV instruction with bit invert
 *  \ingroup pio_instructions
 *
 * This is the equivalent of `MOV <dest>, ~<src>`
 *
 * \param dest The destination to write inverted data to
 * \param src The source to take data from
 * \return The instruction encoding with 0 delay and no side set value
 * \see pio_encode_delay, pio_encode_sideset, pio_encode_sideset_opt
 */
static inline uint pio_encode_mov_not(enum pio_src_dest dest, enum pio_src_dest src) {
    valid_params_if(PIO_INSTRUCTIONS, !(dest & _PIO_INVALID_MOV_DEST));
    valid_params_if(PIO_INSTRUCTIONS, !(src & _PIO_INVALID_MOV_SRC));
    return _pio_encode_instr_and_src_dest(pio_instr_bits_mov, dest, (1u << 3u) | (src & 7u));
}

/*! \brief Encode a MOV instruction with bit reverse
 *  \ingroup pio_instructions
 *
 * This is the equivalent of `MOV <dest>, ::<src>`
 *
 * \param dest The destination to write bit reversed data to
 * \param src The source to take data from
 * \return The instruction encoding with 0 delay and no side set value
 * \see pio_encode_delay, pio_encode_sideset, pio_encode_sideset_opt
 */
static inline uint pio_encode_mov_reverse(enum pio_src_dest dest, enum pio_src_dest src) {
    valid_params_if(PIO_INSTRUCTIONS, !(dest & _PIO_INVALID_MOV_DEST));
    valid_params_if(PIO_INSTRUCTIONS, !(src & _PIO_INVALID_MOV_SRC));
    return _pio_encode_instr_and_src_dest(pio_instr_bits_mov, dest, (2u << 3u) | (src & 7u));
}

/*! \brief Encode a IRQ SET instruction
 *  \ingroup pio_instructions
 *
 * This is the equivalent of `IRQ SET <irq> <relative>`
 *
 * \param relative true for a `IRQ SET <irq> REL`, false for regular `IRQ SET <irq>`
 * \param irq the irq number 0-7
 * \return The instruction encoding with 0 delay and no side set value
 * \see pio_encode_delay, pio_encode_sideset, pio_encode_sideset_opt
 */
static inline uint pio_encode_irq_set(bool relative, uint irq) {
    return _pio_encode_instr_and_args(pio_instr_bits_irq, 0, _pio_encode_irq(relative, irq));
}

/*! \brief Encode a IRQ WAIT instruction
 *  \ingroup pio_instructions
 *
 * This is the equivalent of `IRQ WAIT <irq> <relative>`
 *
 * \param relative true for a `IRQ WAIT <irq> REL`, false for regular `IRQ WAIT <irq>`
 * \param irq the irq number 0-7
 * \return The instruction encoding with 0 delay and no side set value
 * \see pio_encode_delay, pio_encode_sideset, pio_encode_sideset_opt
 */
static inline uint pio_encode_irq_wait(bool relative, uint irq) {
    return _pio_encode_instr_and_args(pio_instr_bits_irq, 1, _pio_encode_irq(relative, irq));
}

/*! \brief Encode a IRQ CLEAR instruction
 *  \ingroup pio_instructions
 *
 * This is the equivalent of `IRQ CLEAR <irq> <relative>`
 *
 * \param relative true for a `IRQ CLEAR <irq> REL`, false for regular `IRQ CLEAR <irq>`
 * \param irq the irq number 0-7
 * \return The instruction encoding with 0 delay and no side set value
 * \see pio_encode_delay, pio_encode_sideset, pio_encode_sideset_opt
 */
static inline uint pio_encode_irq_clear(bool relative, uint irq) {
    return _pio_encode_instr_and_args(pio_instr_bits_irq, 2, _pio_encode_irq(relative, irq));
}

/*! \brief Encode a SET instruction
 *  \ingroup pio_instructions
 *
 * This is the equivalent of `SET <dest>, <value>`
 *
 * \param dest The destination to apply the value to
 * \param value The value 0-31
 * \return The instruction encoding with 0 delay and no side set value
 * \see pio_encode_delay, pio_encode_sideset, pio_encode_sideset_opt
 */
static inline uint pio_encode_set(enum pio_src_dest dest, uint value) {
    valid_params_if(PIO_INSTRUCTIONS, !(dest & _PIO_INVALID_SET_DEST));
    return _pio_encode_instr_and_src_dest(pio_instr_bits_set, dest, value);
}

/*! \brief Encode a NOP instruction
 *  \ingroup pio_instructions
 *
 * This is the equivalent of `NOP` which is itself encoded as `MOV y, y`
 *
 * \return The instruction encoding with 0 delay and no side set value
 * \see pio_encode_delay, pio_encode_sideset, pio_encode_sideset_opt
 */
static inline uint pio_encode_nop(void) {
    return pio_encode_mov(pio_y, pio_y);
}

#ifdef __cplusplus
}
#endif

#endif