// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// +build ignore

package main

import (
	"fmt"
)

// Suffixes encode the bit width of various instructions:
//
// D (double word) = 64 bit int
// W (word)        = 32 bit int
// H (half word)   = 16 bit int
// B (byte)        = 8 bit int
// S (single)      = 32 bit float
// D (double)      = 64 bit float
// L               = 64 bit int, used when the opcode starts with F

const (
	riscv64REG_G    = 4
	riscv64REG_CTXT = 20
	riscv64REG_LR   = 1
	riscv64REG_SP   = 2
	riscv64REG_TMP  = 31
	riscv64REG_ZERO = 0
)

func riscv64RegName(r int) string {
	switch {
	case r == riscv64REG_G:
		return "g"
	case r == riscv64REG_SP:
		return "SP"
	case 0 <= r && r <= 31:
		return fmt.Sprintf("X%d", r)
	case 32 <= r && r <= 63:
		return fmt.Sprintf("F%d", r-32)
	default:
		panic(fmt.Sprintf("unknown register %d", r))
	}
}

func init() {
	var regNamesRISCV64 []string
	var gpMask, fpMask, gpspMask, gpspsbMask regMask
	regNamed := make(map[string]regMask)

	// Build the list of register names, creating an appropriately indexed
	// regMask for the gp and fp registers as we go.
	//
	// If name is specified, use it rather than the riscv reg number.
	addreg := func(r int, name string) regMask {
		mask := regMask(1) << uint(len(regNamesRISCV64))
		if name == "" {
			name = riscv64RegName(r)
		}
		regNamesRISCV64 = append(regNamesRISCV64, name)
		regNamed[name] = mask
		return mask
	}

	// General purpose registers.
	for r := 0; r <= 31; r++ {
		if r == riscv64REG_LR {
			// LR is not used by regalloc, so we skip it to leave
			// room for pseudo-register SB.
			continue
		}

		mask := addreg(r, "")

		// Add general purpose registers to gpMask.
		switch r {
		// ZERO, g, and TMP are not in any gp mask.
		case riscv64REG_ZERO, riscv64REG_G, riscv64REG_TMP:
		case riscv64REG_SP:
			gpspMask |= mask
			gpspsbMask |= mask
		default:
			gpMask |= mask
			gpspMask |= mask
			gpspsbMask |= mask
		}
	}

	// Floating pointer registers.
	for r := 32; r <= 63; r++ {
		mask := addreg(r, "")
		fpMask |= mask
	}

	// Pseudo-register: SB
	mask := addreg(-1, "SB")
	gpspsbMask |= mask

	if len(regNamesRISCV64) > 64 {
		// regMask is only 64 bits.
		panic("Too many RISCV64 registers")
	}

	regCtxt := regNamed["X20"]
	callerSave := gpMask | fpMask | regNamed["g"]

	var (
		gpstore = regInfo{inputs: []regMask{gpspsbMask, gpspMask, 0}} // SB in first input so we can load from a global, but not in second to avoid using SB as a temporary register
		gp01    = regInfo{outputs: []regMask{gpMask}}
		gp11    = regInfo{inputs: []regMask{gpMask}, outputs: []regMask{gpMask}}
		gp21    = regInfo{inputs: []regMask{gpMask, gpMask}, outputs: []regMask{gpMask}}
		gpload  = regInfo{inputs: []regMask{gpspsbMask, 0}, outputs: []regMask{gpMask}}
		gp11sb  = regInfo{inputs: []regMask{gpspsbMask}, outputs: []regMask{gpMask}}

		fp11    = regInfo{inputs: []regMask{fpMask}, outputs: []regMask{fpMask}}
		fp21    = regInfo{inputs: []regMask{fpMask, fpMask}, outputs: []regMask{fpMask}}
		gpfp    = regInfo{inputs: []regMask{gpMask}, outputs: []regMask{fpMask}}
		fpgp    = regInfo{inputs: []regMask{fpMask}, outputs: []regMask{gpMask}}
		fpstore = regInfo{inputs: []regMask{gpspsbMask, fpMask, 0}}
		fpload  = regInfo{inputs: []regMask{gpspsbMask, 0}, outputs: []regMask{fpMask}}
		fp2gp   = regInfo{inputs: []regMask{fpMask, fpMask}, outputs: []regMask{gpMask}}

		call        = regInfo{clobbers: callerSave}
		callClosure = regInfo{inputs: []regMask{gpspMask, regCtxt, 0}, clobbers: callerSave}
		callInter   = regInfo{inputs: []regMask{gpMask}, clobbers: callerSave}
	)

	RISCV64ops := []opData{
		{name: "ADD", argLength: 2, reg: gp21, asm: "ADD", commutative: true}, // arg0 + arg1
		{name: "ADDI", argLength: 1, reg: gp11sb, asm: "ADDI", aux: "Int64"},  // arg0 + auxint
		{name: "SUB", argLength: 2, reg: gp21, asm: "SUB"},                    // arg0 - arg1

		// M extension. H means high (i.e., it returns the top bits of
		// the result). U means unsigned. W means word (i.e., 32-bit).
		{name: "MUL", argLength: 2, reg: gp21, asm: "MUL", commutative: true, typ: "Int64"}, // arg0 * arg1
		{name: "MULW", argLength: 2, reg: gp21, asm: "MULW", commutative: true, typ: "Int32"},
		{name: "MULH", argLength: 2, reg: gp21, asm: "MULH", commutative: true, typ: "Int64"},
		{name: "MULHU", argLength: 2, reg: gp21, asm: "MULHU", commutative: true, typ: "UInt64"},
		{name: "DIV", argLength: 2, reg: gp21, asm: "DIV", typ: "Int64"}, // arg0 / arg1
		{name: "DIVU", argLength: 2, reg: gp21, asm: "DIVU", typ: "UInt64"},
		{name: "DIVW", argLength: 2, reg: gp21, asm: "DIVW", typ: "Int32"},
		{name: "DIVUW", argLength: 2, reg: gp21, asm: "DIVUW", typ: "UInt32"},
		{name: "REM", argLength: 2, reg: gp21, asm: "REM", typ: "Int64"}, // arg0 % arg1
		{name: "REMU", argLength: 2, reg: gp21, asm: "REMU", typ: "UInt64"},
		{name: "REMW", argLength: 2, reg: gp21, asm: "REMW", typ: "Int32"},
		{name: "REMUW", argLength: 2, reg: gp21, asm: "REMUW", typ: "UInt32"},

		{name: "MOVaddr", argLength: 1, reg: gp11sb, asm: "MOV", aux: "SymOff", rematerializeable: true, symEffect: "RdWr"}, // arg0 + auxint + offset encoded in aux
		// auxint+aux == add auxint and the offset of the symbol in aux (if any) to the effective address

		{name: "MOVBconst", reg: gp01, asm: "MOV", typ: "UInt8", aux: "Int8", rematerializeable: true},   // 8 low bits of auxint
		{name: "MOVHconst", reg: gp01, asm: "MOV", typ: "UInt16", aux: "Int16", rematerializeable: true}, // 16 low bits of auxint
		{name: "MOVWconst", reg: gp01, asm: "MOV", typ: "UInt32", aux: "Int32", rematerializeable: true}, // 32 low bits of auxint
		{name: "MOVDconst", reg: gp01, asm: "MOV", typ: "UInt64", aux: "Int64", rematerializeable: true}, // auxint

		// Loads: load <size> bits from arg0+auxint+aux and extend to 64 bits; arg1=mem
		{name: "MOVBload", argLength: 2, reg: gpload, asm: "MOVB", aux: "SymOff", typ: "Int8", faultOnNilArg0: true, symEffect: "Read"},     //  8 bits, sign extend
		{name: "MOVHload", argLength: 2, reg: gpload, asm: "MOVH", aux: "SymOff", typ: "Int16", faultOnNilArg0: true, symEffect: "Read"},    // 16 bits, sign extend
		{name: "MOVWload", argLength: 2, reg: gpload, asm: "MOVW", aux: "SymOff", typ: "Int32", faultOnNilArg0: true, symEffect: "Read"},    // 32 bits, sign extend
		{name: "MOVDload", argLength: 2, reg: gpload, asm: "MOV", aux: "SymOff", typ: "Int64", faultOnNilArg0: true, symEffect: "Read"},     // 64 bits
		{name: "MOVBUload", argLength: 2, reg: gpload, asm: "MOVBU", aux: "SymOff", typ: "UInt8", faultOnNilArg0: true, symEffect: "Read"},  //  8 bits, zero extend
		{name: "MOVHUload", argLength: 2, reg: gpload, asm: "MOVHU", aux: "SymOff", typ: "UInt16", faultOnNilArg0: true, symEffect: "Read"}, // 16 bits, zero extend
		{name: "MOVWUload", argLength: 2, reg: gpload, asm: "MOVWU", aux: "SymOff", typ: "UInt32", faultOnNilArg0: true, symEffect: "Read"}, // 32 bits, zero extend

		// Stores: store <size> lowest bits in arg1 to arg0+auxint+aux; arg2=mem
		{name: "MOVBstore", argLength: 3, reg: gpstore, asm: "MOVB", aux: "SymOff", typ: "Mem", faultOnNilArg0: true, symEffect: "Write"}, //  8 bits
		{name: "MOVHstore", argLength: 3, reg: gpstore, asm: "MOVH", aux: "SymOff", typ: "Mem", faultOnNilArg0: true, symEffect: "Write"}, // 16 bits
		{name: "MOVWstore", argLength: 3, reg: gpstore, asm: "MOVW", aux: "SymOff", typ: "Mem", faultOnNilArg0: true, symEffect: "Write"}, // 32 bits
		{name: "MOVDstore", argLength: 3, reg: gpstore, asm: "MOV", aux: "SymOff", typ: "Mem", faultOnNilArg0: true, symEffect: "Write"},  // 64 bits

		// Shift ops
		{name: "SLL", argLength: 2, reg: gp21, asm: "SLL"},                 // arg0 << aux1
		{name: "SRA", argLength: 2, reg: gp21, asm: "SRA"},                 // arg0 >> aux1, signed
		{name: "SRL", argLength: 2, reg: gp21, asm: "SRL"},                 // arg0 >> aux1, unsigned
		{name: "SLLI", argLength: 1, reg: gp11, asm: "SLLI", aux: "Int64"}, // arg0 << auxint
		{name: "SRAI", argLength: 1, reg: gp11, asm: "SRAI", aux: "Int64"}, // arg0 >> auxint, signed
		{name: "SRLI", argLength: 1, reg: gp11, asm: "SRLI", aux: "Int64"}, // arg0 >> auxint, unsigned

		// Bitwise ops
		{name: "XOR", argLength: 2, reg: gp21, asm: "XOR", commutative: true}, // arg0 ^ arg1
		{name: "XORI", argLength: 1, reg: gp11, asm: "XORI", aux: "Int64"},    // arg0 ^ auxint
		{name: "OR", argLength: 2, reg: gp21, asm: "OR", commutative: true},   // arg0 | arg1
		{name: "ORI", argLength: 1, reg: gp11, asm: "ORI", aux: "Int64"},      // arg0 | auxint
		{name: "AND", argLength: 2, reg: gp21, asm: "AND", commutative: true}, // arg0 & arg1
		{name: "ANDI", argLength: 1, reg: gp11, asm: "ANDI", aux: "Int64"},    // arg0 & auxint

		// Generate boolean values
		{name: "SEQZ", argLength: 1, reg: gp11, asm: "SEQZ"},                 // arg0 == 0, result is 0 or 1
		{name: "SNEZ", argLength: 1, reg: gp11, asm: "SNEZ"},                 // arg0 != 0, result is 0 or 1
		{name: "SLT", argLength: 2, reg: gp21, asm: "SLT"},                   // arg0 < arg1, result is 0 or 1
		{name: "SLTI", argLength: 1, reg: gp11, asm: "SLTI", aux: "Int64"},   // arg0 < auxint, result is 0 or 1
		{name: "SLTU", argLength: 2, reg: gp21, asm: "SLTU"},                 // arg0 < arg1, unsigned, result is 0 or 1
		{name: "SLTIU", argLength: 1, reg: gp11, asm: "SLTIU", aux: "Int64"}, // arg0 < auxint, unsigned, result is 0 or 1

		// MOVconvert converts between pointers and integers.
		// We have a special op for this so as to not confuse GC
		// (particularly stack maps). It takes a memory arg so it
		// gets correctly ordered with respect to GC safepoints.
		{name: "MOVconvert", argLength: 2, reg: gp11, asm: "MOV"}, // arg0, but converted to int/ptr as appropriate; arg1=mem

		// Calls
		{name: "CALLstatic", argLength: 1, reg: call, aux: "SymOff", call: true, symEffect: "None"}, // call static function aux.(*gc.Sym). arg0=mem, auxint=argsize, returns mem
		{name: "CALLclosure", argLength: 3, reg: callClosure, aux: "Int64", call: true},             // call function via closure. arg0=codeptr, arg1=closure, arg2=mem, auxint=argsize, returns mem
		{name: "CALLinter", argLength: 2, reg: callInter, aux: "Int64", call: true},                 // call fn by pointer. arg0=codeptr, arg1=mem, auxint=argsize, returns mem

		// Generic moves and zeros

		// general unaligned zeroing
		// arg0 = address of memory to zero (in X5, changed as side effect)
		// arg1 = address of the last element to zero (inclusive)
		// arg2 = mem
		// auxint = element size
		// returns mem
		//	mov	ZERO, (X5)
		//	ADD	$sz, X5
		//	BGEU	Rarg1, X5, -2(PC)
		{
			name:      "LoweredZero",
			aux:       "Int64",
			argLength: 3,
			reg: regInfo{
				inputs:   []regMask{regNamed["X5"], gpMask},
				clobbers: regNamed["X5"],
			},
			typ:            "Mem",
			faultOnNilArg0: true,
		},

		// general unaligned move
		// arg0 = address of dst memory (in X5, changed as side effect)
		// arg1 = address of src memory (in X6, changed as side effect)
		// arg2 = address of the last element of src (can't be X7 as we clobber it before using arg2)
		// arg3 = mem
		// auxint = alignment
		// clobbers X7 as a tmp register.
		// returns mem
		//	mov	(X6), X7
		//	mov	X7, (X5)
		//	ADD	$sz, X5
		//	ADD	$sz, X6
		//	BGEU	Rarg2, X5, -4(PC)
		{
			name:      "LoweredMove",
			aux:       "Int64",
			argLength: 4,
			reg: regInfo{
				inputs:   []regMask{regNamed["X5"], regNamed["X6"], gpMask &^ regNamed["X7"]},
				clobbers: regNamed["X5"] | regNamed["X6"] | regNamed["X7"],
			},
			typ:            "Mem",
			faultOnNilArg0: true,
			faultOnNilArg1: true,
		},

		// Lowering pass-throughs
		{name: "LoweredNilCheck", argLength: 2, faultOnNilArg0: true, nilCheck: true, reg: regInfo{inputs: []regMask{gpspMask}}}, // arg0=ptr,arg1=mem, returns void.  Faults if ptr is nil.
		{name: "LoweredGetClosurePtr", reg: regInfo{outputs: []regMask{regCtxt}}},                                                // scheduler ensures only at beginning of entry block

		// LoweredGetCallerSP returns the SP of the caller of the current function.
		{name: "LoweredGetCallerSP", reg: gp01, rematerializeable: true},

		// LoweredGetCallerPC evaluates to the PC to which its "caller" will return.
		// I.e., if f calls g "calls" getcallerpc,
		// the result should be the PC within f that g will return to.
		// See runtime/stubs.go for a more detailed discussion.
		{name: "LoweredGetCallerPC", reg: gp01, rematerializeable: true},

		// LoweredWB invokes runtime.gcWriteBarrier. arg0=destptr, arg1=srcptr, arg2=mem, aux=runtime.gcWriteBarrier
		// It saves all GP registers if necessary,
		// but clobbers RA (LR) because it's a call
		// and T6 (REG_TMP).
		{name: "LoweredWB", argLength: 3, reg: regInfo{inputs: []regMask{regNamed["X5"], regNamed["X6"]}, clobbers: (callerSave &^ (gpMask | regNamed["g"])) | regNamed["X1"]}, clobberFlags: true, aux: "Sym", symEffect: "None"},

		// There are three of these functions so that they can have three different register inputs.
		// When we check 0 <= c <= cap (A), then 0 <= b <= c (B), then 0 <= a <= b (C), we want the
		// default registers to match so we don't need to copy registers around unnecessarily.
		{name: "LoweredPanicBoundsA", argLength: 3, aux: "Int64", reg: regInfo{inputs: []regMask{regNamed["X7"], regNamed["X28"]}}, typ: "Mem"}, // arg0=idx, arg1=len, arg2=mem, returns memory. AuxInt contains report code (see PanicBounds in genericOps.go).
		{name: "LoweredPanicBoundsB", argLength: 3, aux: "Int64", reg: regInfo{inputs: []regMask{regNamed["X6"], regNamed["X7"]}}, typ: "Mem"},  // arg0=idx, arg1=len, arg2=mem, returns memory. AuxInt contains report code (see PanicBounds in genericOps.go).
		{name: "LoweredPanicBoundsC", argLength: 3, aux: "Int64", reg: regInfo{inputs: []regMask{regNamed["X5"], regNamed["X6"]}}, typ: "Mem"},  // arg0=idx, arg1=len, arg2=mem, returns memory. AuxInt contains report code (see PanicBounds in genericOps.go).

		// F extension.
		{name: "FADDS", argLength: 2, reg: fp21, asm: "FADDS", commutative: true, typ: "Float32"},                                           // arg0 + arg1
		{name: "FSUBS", argLength: 2, reg: fp21, asm: "FSUBS", commutative: false, typ: "Float32"},                                          // arg0 - arg1
		{name: "FMULS", argLength: 2, reg: fp21, asm: "FMULS", commutative: true, typ: "Float32"},                                           // arg0 * arg1
		{name: "FDIVS", argLength: 2, reg: fp21, asm: "FDIVS", commutative: false, typ: "Float32"},                                          // arg0 / arg1
		{name: "FSQRTS", argLength: 1, reg: fp11, asm: "FSQRTS", typ: "Float32"},                                                            // sqrt(arg0)
		{name: "FNEGS", argLength: 1, reg: fp11, asm: "FNEGS", typ: "Float32"},                                                              // -arg0
		{name: "FMVSX", argLength: 1, reg: gpfp, asm: "FMVSX", typ: "Float32"},                                                              // reinterpret arg0 as float
		{name: "FCVTSW", argLength: 1, reg: gpfp, asm: "FCVTSW", typ: "Float32"},                                                            // float32(low 32 bits of arg0)
		{name: "FCVTSL", argLength: 1, reg: gpfp, asm: "FCVTSL", typ: "Float32"},                                                            // float32(arg0)
		{name: "FCVTWS", argLength: 1, reg: fpgp, asm: "FCVTWS", typ: "Int32"},                                                              // int32(arg0)
		{name: "FCVTLS", argLength: 1, reg: fpgp, asm: "FCVTLS", typ: "Int64"},                                                              // int64(arg0)
		{name: "FMOVWload", argLength: 2, reg: fpload, asm: "MOVF", aux: "SymOff", typ: "Float32", faultOnNilArg0: true, symEffect: "Read"}, // load float32 from arg0+auxint+aux
		{name: "FMOVWstore", argLength: 3, reg: fpstore, asm: "MOVF", aux: "SymOff", typ: "Mem", faultOnNilArg0: true, symEffect: "Write"},  // store float32 to arg0+auxint+aux
		{name: "FEQS", argLength: 2, reg: fp2gp, asm: "FEQS", commutative: true},                                                            // arg0 == arg1
		{name: "FNES", argLength: 2, reg: fp2gp, asm: "FNES", commutative: true},                                                            // arg0 != arg1
		{name: "FLTS", argLength: 2, reg: fp2gp, asm: "FLTS"},                                                                               // arg0 < arg1
		{name: "FLES", argLength: 2, reg: fp2gp, asm: "FLES"},                                                                               // arg0 <= arg1

		// D extension.
		{name: "FADDD", argLength: 2, reg: fp21, asm: "FADDD", commutative: true, typ: "Float64"},                                           // arg0 + arg1
		{name: "FSUBD", argLength: 2, reg: fp21, asm: "FSUBD", commutative: false, typ: "Float64"},                                          // arg0 - arg1
		{name: "FMULD", argLength: 2, reg: fp21, asm: "FMULD", commutative: true, typ: "Float64"},                                           // arg0 * arg1
		{name: "FDIVD", argLength: 2, reg: fp21, asm: "FDIVD", commutative: false, typ: "Float64"},                                          // arg0 / arg1
		{name: "FSQRTD", argLength: 1, reg: fp11, asm: "FSQRTD", typ: "Float64"},                                                            // sqrt(arg0)
		{name: "FNEGD", argLength: 1, reg: fp11, asm: "FNEGD", typ: "Float64"},                                                              // -arg0
		{name: "FMVDX", argLength: 1, reg: gpfp, asm: "FMVDX", typ: "Float64"},                                                              // reinterpret arg0 as float
		{name: "FCVTDW", argLength: 1, reg: gpfp, asm: "FCVTDW", typ: "Float64"},                                                            // float64(low 32 bits of arg0)
		{name: "FCVTDL", argLength: 1, reg: gpfp, asm: "FCVTDL", typ: "Float64"},                                                            // float64(arg0)
		{name: "FCVTWD", argLength: 1, reg: fpgp, asm: "FCVTWD", typ: "Int32"},                                                              // int32(arg0)
		{name: "FCVTLD", argLength: 1, reg: fpgp, asm: "FCVTLD", typ: "Int64"},                                                              // int64(arg0)
		{name: "FCVTDS", argLength: 1, reg: fp11, asm: "FCVTDS", typ: "Float64"},                                                            // float64(arg0)
		{name: "FCVTSD", argLength: 1, reg: fp11, asm: "FCVTSD", typ: "Float32"},                                                            // float32(arg0)
		{name: "FMOVDload", argLength: 2, reg: fpload, asm: "MOVD", aux: "SymOff", typ: "Float64", faultOnNilArg0: true, symEffect: "Read"}, // load float64 from arg0+auxint+aux
		{name: "FMOVDstore", argLength: 3, reg: fpstore, asm: "MOVD", aux: "SymOff", typ: "Mem", faultOnNilArg0: true, symEffect: "Write"},  // store float6 to arg0+auxint+aux
		{name: "FEQD", argLength: 2, reg: fp2gp, asm: "FEQD", commutative: true},                                                            // arg0 == arg1
		{name: "FNED", argLength: 2, reg: fp2gp, asm: "FNED", commutative: true},                                                            // arg0 != arg1
		{name: "FLTD", argLength: 2, reg: fp2gp, asm: "FLTD"},                                                                               // arg0 < arg1
		{name: "FLED", argLength: 2, reg: fp2gp, asm: "FLED"},                                                                               // arg0 <= arg1
	}

	RISCV64blocks := []blockData{
		{name: "BNE", controls: 1}, // Control != 0 (take a register)
	}

	archs = append(archs, arch{
		name:            "RISCV64",
		pkg:             "cmd/internal/obj/riscv",
		genfile:         "../../riscv64/ssa.go",
		ops:             RISCV64ops,
		blocks:          RISCV64blocks,
		regnames:        regNamesRISCV64,
		gpregmask:       gpMask,
		fpregmask:       fpMask,
		framepointerreg: -1, // not used
	})
}