gasm-sdk/asm/riscv_encode_test.go

// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
// SPDX-License-Identifier: BSD-3-Clause

package asm

import (
	"bytes"
	"encoding/binary"
	"encoding/hex"
	"strings"
	"testing"

	"sourcedock.dev/petrbalvin/gasm-devkit/ast"
	"sourcedock.dev/petrbalvin/gasm-devkit/parser"
)

// firstTextRISCV parses assembly source and returns the first TEXT function body.
func firstTextRISCV(t *testing.T, src string) *ast.Text {
	t.Helper()
	f, errs := parser.Parse("f_riscv64.s", src)
	if len(errs) > 0 {
		t.Fatalf("parse: %v", errs)
	}
	for _, d := range f.Decls {
		if fn, ok := d.(*ast.Text); ok {
			return fn
		}
	}
	t.Fatal("no TEXT found")
	return nil
}

// assembleRISCVHelper assembles one TEXT function and returns its code bytes.
func assembleRISCVHelper(t *testing.T, fn *ast.Text) []byte {
	t.Helper()
	code, _, _, _, _, err := assembleRISCV(fn)
	if err != nil {
		t.Fatalf("assemble: %v", err)
	}
	return code
}

func TestRISCV_add(t *testing.T) {
	// func add(a, b int64) int64
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·add(SB), NOSPLIT, $0-24
	MOV a+0(FP), X10
	MOV b+8(FP), X11
	ADD X11, X10, X10
	MOV X10, ret+16(FP)
	RET
`)
	code := assembleRISCVHelper(t, fn)
	// should be 12 bytes with RVC: C.LDSP + C.LDSP + ADD + C.SDSP + C.JR
	_ = code
	if len(code) == 0 {
		t.Error("empty output")
	}
}

func TestRISCV_arithmetic(t *testing.T) {
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·arith(SB), NOSPLIT, $0
	ADD X10, X11, X12
	SUB X12, X13, X14
	MUL X14, X15, X16
	DIV X16, X17, X18
	REM X18, X19, X20
	RET
`)
	code := assembleRISCVHelper(t, fn)
	// 5 R-type instructions + RET = 5*4 + 4 = 24
	if len(code) != 24 {
		t.Errorf("expected 24 bytes, got %d", len(code))
	}
}

func TestRISCV_loadStore(t *testing.T) {
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·mem(SB), NOSPLIT, $0
	LD (X10), X11
	SD X11, (X12)
	LW (X13), X14
	SW X14, (X15)
	RET
`)
	code := assembleRISCVHelper(t, fn)
	// Four register-relative loads/stores compress (2B each) + JALR (4B) = 12.
	if len(code) != 12 {
		t.Errorf("expected 12 bytes, got %d", len(code))
	}
}

func TestRISCV_immediate(t *testing.T) {
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·imm(SB), NOSPLIT, $0
	ADDI $42, X10, X11
	ANDI $0xFF, X11, X12
	ORI $1, X12, X13
	XORI $0, X13, X14
	RET
`)
	code := assembleRISCVHelper(t, fn)
	// 4 I-type + JALR = 4*4 + 4 = 20
	if len(code) != 20 {
		t.Errorf("expected 20 bytes, got %d", len(code))
	}
}

func TestRISCV_branches(t *testing.T) {
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·br(SB), NOSPLIT, $0
	ADDI $1, X10, X10
loop:
	BEQ X10, X11, done
	ADDI $1, X10, X10
	JMP loop
done:
	RET
`)
	code := assembleRISCVHelper(t, fn)
	_ = code
	if len(code) == 0 {
		t.Error("empty output")
	}
}

func TestRISCV_MOV_imm_small(t *testing.T) {
	// MOV $42, rd → ADDI (fits in 12 bits, but not C.LI's 6-bit immediate).
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·small(SB), NOSPLIT, $0
	MOV $42, X10
	RET
`)
	code := assembleRISCVHelper(t, fn)
	// ADDI (4B) + JALR (4B) = 8
	if len(code) != 8 {
		t.Errorf("expected 8 bytes, got %d", len(code))
	}
}

func TestRISCV_MOV_imm_large(t *testing.T) {
	// MOV $0x12345, rd → C.LUI $18 (2B) + ADDIW $837 (4B).
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·large(SB), NOSPLIT, $0
	MOV $0x12345, X10
	RET
`)
	code := assembleRISCVHelper(t, fn)
	// C.LUI (2B) + ADDIW (4B) + JALR (4B) = 10
	if len(code) != 10 {
		t.Errorf("expected 10 bytes, got %d", len(code))
	}
}

func TestRISCV_MOV_reg(t *testing.T) {
	// MOV rs, rd → ADDI $0, rs, rd, compresses to C.MV
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·reg(SB), NOSPLIT, $0
	MOV X10, X11
	RET
`)
	code := assembleRISCVHelper(t, fn)
	// C.MV (2B) + JALR (4B) = 6
	if len(code) != 6 {
		t.Errorf("expected 6 bytes, got %d (% x)", len(code), code)
	}
}

func TestRISCV_MOV_frame(t *testing.T) {
	// MOV name+off(FP), rd → load with frame mapping
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·frame(SB), NOSPLIT, $0-8
	MOV a+0(FP), X10
	MOV X10, ret+0(FP)
	RET
`)
	code := assembleRISCVHelper(t, fn)
	// C.LDSP (2B) + C.SDSP (2B) + JALR (4B) = 8
	if len(code) != 8 {
		t.Errorf("expected 8 bytes, got %d", len(code))
	}
}

func TestRISCV_RVC_loadStore(t *testing.T) {
	// Verify that loads/stores from SP are compressed.
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·rvcstore(SB), NOSPLIT, $0
	LD 0(SP), X10
	SD X10, 8(SP)
	RET
`)
	code := assembleRISCVHelper(t, fn)
	// C.LDSP (2B) + C.SDSP (2B) + JALR (4B) = 8
	if len(code) != 8 {
		t.Errorf("expected 8 bytes, got %d (% x)", len(code), code)
	}
}

func TestRISCV_atomics(t *testing.T) {
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·amo(SB), NOSPLIT, $0
	AMOADDD X10, (X11), X12
	LRD (X13), X14
	SCD X15, (X16), X17
	RET
`)
	code := assembleRISCVHelper(t, fn)
	// 3 AMO instructions (4B each) + JALR (4B) = 16
	if len(code) != 16 {
		t.Errorf("expected 16 bytes, got %d", len(code))
	}
}

func TestRISCV_fpArith(t *testing.T) {
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·fpadd(SB), NOSPLIT, $0
	FADDD F10, F11, F12
	FSUBD F12, F13, F14
	FMULD F14, F15, F16
	FDIVD F16, F17, F18
	FSQRTD F18, F19
	RET
`)
	code := assembleRISCVHelper(t, fn)
	// 5 FP instructions (4B each) + JALR (4B) = 24
	if len(code) != 24 {
		t.Errorf("expected 24 bytes, got %d (%d)", len(code), len(code))
	}
}

func TestRISCV_csr(t *testing.T) {
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·csrtest(SB), NOSPLIT, $0
	CSRRS $0x300, X0, X10
	CSRRW $0x305, X10, X11
	CSRRSI $0x304, $5, X12
	RET
`)
	code := assembleRISCVHelper(t, fn)
	// 3 CSR instructions (4B each) + JALR (4B) = 16
	if len(code) != 16 {
		t.Errorf("expected 16 bytes, got %d", len(code))
	}
}

func TestRISCV_fma(t *testing.T) {
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·fmatest(SB), NOSPLIT, $0
	FMADDD F10, F11, F12, F13
	FMSUBD F13, F14, F15, F16
	FNMSUBD F16, F17, F18, F19
	FNMADDD F19, F10, F11, F12
	RET
`)
	code := assembleRISCVHelper(t, fn)
	// 4 FMA instructions (4B each) + JALR (4B) = 20
	if len(code) != 20 {
		t.Errorf("expected 20 bytes, got %d", len(code))
	}
}

func TestRISCV_conversions(t *testing.T) {
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·cvt(SB), NOSPLIT, $0
	FCVTDL X10, F10
	FCVTLD F10, X11
	FMVXD F10, X12
	FMVDX X12, F11
	RET
`)
	code := assembleRISCVHelper(t, fn)
	// 4 conversion instructions (4B each) + JALR (4B) = 20
	if len(code) != 20 {
		t.Errorf("expected 20 bytes, got %d", len(code))
	}
}

func TestRISCV_fpCmp(t *testing.T) {
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·cmp(SB), NOSPLIT, $0
	FEQD F10, F11, X10
	FLTD F12, F13, X11
	FLED F14, F15, X12
	RET
`)
	code := assembleRISCVHelper(t, fn)
	// 3 FP compare (4B each) + JALR (4B) = 16
	if len(code) != 16 {
		t.Errorf("expected 16 bytes, got %d", len(code))
	}
}

func TestRISCV_forwardBranch(t *testing.T) {
	// Forward label reference; must not fail.
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·fwd(SB), NOSPLIT, $0
	ADDI $1, X10, X10
	BEQ X10, X11, done
	ADDI $1, X10, X10
done:
	RET
`)
	code := assembleRISCVHelper(t, fn)
	_ = code
	if len(code) == 0 {
		t.Error("empty output")
	}
}

func TestRISCV_RVC_ADDI(t *testing.T) {
	// ADDI where rd=rs1 and small imm → C.ADDI
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·caddi(SB), NOSPLIT, $0
	ADDI $5, X10, X10
	RET
`)
	code := assembleRISCVHelper(t, fn)
	// C.ADDI (2B) + JALR (4B) = 6
	if len(code) != 6 {
		t.Errorf("expected 6 bytes, got %d", len(code))
	}
}

func TestRISCV_RVC_LI(t *testing.T) {
	// ADDI X0, $imm, rd → C.LI
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·cli(SB), NOSPLIT, $0
	ADDI $7, X0, X10
	RET
`)
	code := assembleRISCVHelper(t, fn)
	// C.LI (2B) + JALR (4B) = 6
	if len(code) != 6 {
		t.Errorf("expected 6 bytes, got %d", len(code))
	}
}

func TestRISCV_RVC_LUI(t *testing.T) {
	// LUI rd, small nonzero imm → C.LUI
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·clui(SB), NOSPLIT, $0
	LUI X10, $1
	RET
`)
	code := assembleRISCVHelper(t, fn)
	// C.LUI (2B) + JALR (4B) = 6
	if len(code) != 6 {
		t.Errorf("expected 6 bytes, got %d", len(code))
	}
}

func TestRISCV_AssembleFile(t *testing.T) {
	src := `#include "textflag.h"

TEXT ·add(SB), NOSPLIT, $0-24
	MOV a+0(FP), X10
	RET

TEXT ·sub(SB), NOSPLIT, $0
	SUB X10, X11, X12
	RET
`
	f, errs := parser.Parse("t_riscv64.s", src)
	if len(errs) > 0 {
		t.Fatalf("parse: %v", errs)
	}
	img, err := AssembleFileRISCV(f)
	if err != nil {
		t.Fatalf("AssembleFileRISCV: %v", err)
	}
	if len(img.Funcs) != 2 {
		t.Fatalf("expected 2 functions, got %d", len(img.Funcs))
	}
	// func add: C.LDSP(2) + JALR(4) = 6
	if img.Funcs[0].Size != 6 {
		t.Errorf("add: expected 6 bytes, got %d", img.Funcs[0].Size)
	}
	// func sub: SUB(4) + JALR(4) = 8
	if img.Funcs[1].Size != 8 {
		t.Errorf("sub: expected 8 bytes, got %d", img.Funcs[1].Size)
	}
}

func TestRISCV_encodings(t *testing.T) {
	// Smoke test that all known RISC-V mnemonics encode successfully.
	tests := []struct {
		name, src string
		wantBytes int
	}{
		{"ADD", "ADD X10, X11, X12\nRET\n", 8},
		{"SUBW", "SUBW X10, X11, X12\nRET\n", 8},
		{"MUL", "MUL X10, X11, X12\nRET\n", 8},
		{"DIVW", "DIVW X10, X11, X12\nRET\n", 8},
		{"REMUW", "REMUW X10, X11, X12\nRET\n", 8},
		{"ADDIW", "ADDIW $5, X10, X11\nRET\n", 8},
		{"SLLI", "SLLI $3, X10, X11\nRET\n", 8}, // ADDI+SLLI? No, SLLI uses I-type
		{"SRLI", "SRLI $2, X10, X11\nRET\n", 8},
		{"SRAI", "SRAI $1, X10, X11\nRET\n", 8},
		{"LB", "LB (X10), X11\nRET\n", 8},
		{"LBU", "LBU (X10), X11\nRET\n", 8},
		{"LH", "LH (X10), X11\nRET\n", 8},
		{"LHU", "LHU (X10), X11\nRET\n", 8},
		{"LWU", "LWU (X10), X11\nRET\n", 8},
		{"SB", "SB X10, (X11)\nRET\n", 8},
		{"SH", "SH X10, (X11)\nRET\n", 8},
		{"SW", "SW X10, (X11)\nRET\n", 6},
		{"LUI", "LUI X10, $0x12345\nRET\n", 8},
		{"AUIPC", "AUIPC X10, $0\nRET\n", 8},
		{"FLW", "FLW (X10), F10\nRET\n", 8},
		{"FSW", "FSW F10, (X11)\nRET\n", 8},
		{"FADDS", "FADDS F10, F11, F12\nRET\n", 8},
		{"FMINS", "FMINS F10, F11, F12\nRET\n", 8},
		{"FMAXD", "FMAXD F10, F11, F12\nRET\n", 8},
		{"FCVTSD", "FCVTSD F10, F11\nRET\n", 8},
		{"FCVTDS", "FCVTDS F10, F11\nRET\n", 8},
		{"FMVXW", "FMVXW F10, X10\nRET\n", 8},
		{"FMADD_S", "FMADDS F10, F11, F12, F13\nRET\n", 8},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·`+tt.name+`(SB), NOSPLIT, $0
	`+tt.src)
			code := assembleRISCVHelper(t, fn)
			if len(code) != tt.wantBytes {
				t.Errorf("expected %d bytes, got %d", tt.wantBytes, len(code))
			}
		})
	}
}

func TestRISCV_RVC_branch(t *testing.T) {
	// Branches are never RVC-compressed (no C.BEQZ/C.BNEZ), matching go tool asm.
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·cbeqz(SB), NOSPLIT, $0
	ADDI $1, X10, X10
	BEQ X10, X0, done
	ADDI $1, X10, X10
done:
	RET
`)
	code := assembleRISCVHelper(t, fn)
	// C.ADDI(2) + BEQ(4) + C.ADDI(2) + JALR(4) = 12
	if len(code) != 12 {
		t.Errorf("expected 12 bytes with uncompressed BEQ, got %d", len(code))
	}
}

func TestRISCV_RVC_CJ(t *testing.T) {
	// JMP target → JAL X0 (never compressed to C.J), matching go tool asm.
	fn := firstTextRISCV(t, `#include "textflag.h"
	TEXT ·cj(SB), NOSPLIT, $0
		JMP done
	done:
		RET
	`)
	code := assembleRISCVHelper(t, fn)
	// JAL(4) + JALR(4) = 8
	if len(code) != 8 {
		t.Errorf("expected 8 bytes with uncompressed JMP, got %d", len(code))
	}
}

func TestRISCV_RVC_CADD(t *testing.T) {
	// ADD where rd==rs1 and both in prime regs → C.ADD.
	fn := firstTextRISCV(t, `#include "textflag.h"
	TEXT ·cadd(SB), NOSPLIT, $0
		ADD X10, X11, X10
		RET
	`)
	code := assembleRISCVHelper(t, fn)
	// C.ADD(2) + JALR(4) = 6
	if len(code) != 6 {
		t.Errorf("expected 6 bytes with C.ADD, got %d", len(code))
	}
}

func TestRISCV_RVC_CADD_commute(t *testing.T) {
	// ADD where rd==rs2 (commutative swap) → C.ADD.
	fn := firstTextRISCV(t, `#include "textflag.h"
	TEXT ·cadd2(SB), NOSPLIT, $0
		ADD X11, X10, X10
		RET
	`)
	code := assembleRISCVHelper(t, fn)
	// C.ADD(2) + JALR(4) = 6
	if len(code) != 6 {
		t.Errorf("expected 6 bytes with C.ADD (commuted), got %d", len(code))
	}
}

func TestRISCV_RVC_CSUB(t *testing.T) {
	// SUB rs2, rs1, rd → C.SUB when rd == rs1 and both in prime regs.
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·csub(SB), NOSPLIT, $0
	SUB X11, X10, X10
	RET
`)
	code := assembleRISCVHelper(t, fn)
	// SUB X11, X10, X10 → rs2=X11, rs1=X10, rd=X10; rd==rs1 → C.SUB (2B) + JALR (4B) = 6.
	if len(code) != 6 {
		t.Errorf("expected 6 bytes with C.SUB, got %d (% x)", len(code), code)
	}
}

func TestRISCV_RVC_CXOR(t *testing.T) {
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·cxor(SB), NOSPLIT, $0
	XOR X10, X11, X10
	RET
`)
	code := assembleRISCVHelper(t, fn)
	if len(code) != 6 {
		t.Errorf("expected 6 bytes with C.XOR, got %d", len(code))
	}
}

func TestRISCV_RVC_COR(t *testing.T) {
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·cor(SB), NOSPLIT, $0
	OR X10, X11, X10
	RET
`)
	code := assembleRISCVHelper(t, fn)
	if len(code) != 6 {
		t.Errorf("expected 6 bytes with C.OR, got %d", len(code))
	}
}

func TestRISCV_RVC_CAND(t *testing.T) {
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·cand(SB), NOSPLIT, $0
	AND X10, X11, X10
	RET
`)
	code := assembleRISCVHelper(t, fn)
	if len(code) != 6 {
		t.Errorf("expected 6 bytes with C.AND, got %d", len(code))
	}
}

func TestRISCV_RVC_CFLDSP(t *testing.T) {
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·cfldsp(SB), NOSPLIT, $0-8
	FLD a+0(FP), F10
	RET
`)
	code := assembleRISCVHelper(t, fn)
	// C.FLDSP(2) + JALR(4) = 6
	if len(code) != 6 {
		t.Errorf("expected 6 bytes with C.FLDSP, got %d", len(code))
	}
}

func TestRISCV_RVC_CFSDSP(t *testing.T) {
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·cfsdsp(SB), NOSPLIT, $0-8
	FSD F10, ret+0(FP)
	RET
`)
	code := assembleRISCVHelper(t, fn)
	// C.FSDSP(2) + JALR(4) = 6
	if len(code) != 6 {
		t.Errorf("expected 6 bytes with C.FSDSP, got %d", len(code))
	}
}

func TestRISCV_SB_addr(t *testing.T) {
	// MOV $sym<>(SB), rd → AUIPC + ADDI (8 bytes for SB).
	src := `#include "textflag.h"
TEXT ·sbaddr(SB), NOSPLIT, $0
	MOV $answer<>(SB), X10
	RET
GLOBL answer<>(SB), RODATA, $8
DATA answer<>+0(SB)/8, $42
`
	f, errs := parser.Parse("t_riscv64.s", src)
	if len(errs) > 0 {
		t.Fatalf("parse: %v", errs)
	}
	img, err := AssembleFileRISCV(f)
	if err != nil {
		t.Fatalf("AssembleFileRISCV: %v", err)
	}
	// AUIPC(4) + ADDI(4) + JALR(4) = 12
	if img.Funcs[0].Size != 12 {
		t.Errorf("expected 12 bytes, got %d", img.Funcs[0].Size)
	}
}

func TestRISCV_SB_store(t *testing.T) {
	// MOV rd, sym<>(SB) → AUIPC + SD (8 bytes for SB).
	src := `#include "textflag.h"
TEXT ·sbstore(SB), NOSPLIT, $0
	MOV X10, result<>(SB)
	RET
GLOBL result<>(SB), NOPTR, $8
`
	f, errs := parser.Parse("t_riscv64.s", src)
	if len(errs) > 0 {
		t.Fatalf("parse: %v", errs)
	}
	img, err := AssembleFileRISCV(f)
	if err != nil {
		t.Fatalf("AssembleFileRISCV: %v", err)
	}
	// AUIPC X31(4) + SD X10,0(X31)(4) + JALR(4) = 12
	if img.Funcs[0].Size != 12 {
		t.Errorf("expected 12 bytes, got %d", img.Funcs[0].Size)
	}
}

func TestRISCV_ELF(t *testing.T) {
	src := `#include "textflag.h"
TEXT ·simple(SB), NOSPLIT, $0
	RET
`
	f, errs := parser.Parse("t_riscv64.s", src)
	if len(errs) > 0 {
		t.Fatalf("parse: %v", errs)
	}
	img, err := AssembleFileRISCV(f)
	if err != nil {
		t.Fatalf("AssembleFileRISCV: %v", err)
	}
	obj, err := img.ELFRISCVObject()
	if err != nil {
		t.Fatalf("ELFRISCVObject: %v", err)
	}
	if len(obj) < 4 || obj[0] != 0x7f || obj[1] != 'E' || obj[2] != 'L' || obj[3] != 'F' {
		t.Fatal("not a valid ELF file")
	}
	if len(obj) >= 20 {
		machine := uint16(obj[18]) | uint16(obj[19])<<8
		if machine != 243 {
			t.Errorf("e_machine = %d, want 243 (EM_RISCV)", machine)
		}
	}
}

func TestRISCV_ELF_withData(t *testing.T) {
	src := `#include "textflag.h"
TEXT ·get(SB), NOSPLIT, $0
	RET
GLOBL val<>(SB), RODATA, $4
DATA val<>+0(SB)/4, $7
`
	f, errs := parser.Parse("t_riscv64.s", src)
	if len(errs) > 0 {
		t.Fatalf("parse: %v", errs)
	}
	img, err := AssembleFileRISCV(f)
	if err != nil {
		t.Fatalf("AssembleFileRISCV: %v", err)
	}
	if len(img.DataSyms) != 1 {
		t.Fatalf("expected 1 data symbol, got %d", len(img.DataSyms))
	}
	if img.DataSyms[0].Name != "val" {
		t.Errorf("data symbol name = %q, want val", img.DataSyms[0].Name)
	}
	if img.DataSyms[0].Size != 4 {
		t.Errorf("data symbol size = %d, want 4", img.DataSyms[0].Size)
	}
	obj, err := img.ELFRISCVObject()
	if err != nil {
		t.Fatalf("ELFRISCVObject: %v", err)
	}
	_ = obj
}

func TestRISCV_SB_load(t *testing.T) {
	// MOV sym<>(SB), rd → AUIPC + LD (8 bytes for SB).
	src := `#include "textflag.h"
TEXT ·sbload(SB), NOSPLIT, $0
	MOV answer<>(SB), X10
	RET
GLOBL answer<>(SB), RODATA, $8
DATA answer<>+0(SB)/8, $42
`
	f, errs := parser.Parse("t_riscv64.s", src)
	if len(errs) > 0 {
		t.Fatalf("parse: %v", errs)
	}
	img, err := AssembleFileRISCV(f)
	if err != nil {
		t.Fatalf("AssembleFileRISCV: %v", err)
	}
	// AUIPC(4) + LD(4) + JALR(4) = 12
	if img.Funcs[0].Size != 12 {
		t.Errorf("expected 12 bytes, got %d", img.Funcs[0].Size)
	}
}

// TestRISCV_RVC_StorePatterns pins the register-relative compressed store
// encodings for offsets with immediate bits 4 and 5 set, byte-identical to
// the toolchain's encodeCS (patterns {5,4,3,7,6} and {5,4,3,2,6}).
// Regression: the store-side patterns dropped imm[4], so every such store
// silently encoded the wrong address while the loads stayed correct.
func TestRISCV_RVC_StorePatterns(t *testing.T) {
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·csstores(SB), NOSPLIT, $0
	SD  X9, 24(X8)
	SW  X10, 16(X11)
	FSD F8, 40(X12)
	LD  24(X8), X9
	LW  16(X11), X10
	FLD 40(X12), F8
	RET
`)
	code := assembleRISCVHelper(t, fn)
	want := []byte{
		0x04, 0xec, // c.sd x9, 24(x8)
		0x88, 0xc9, // c.sw x10, 16(x11)
		0x00, 0xb6, // c.fsd f8, 40(x12)
		0x04, 0x6c, // c.ld x9, 24(x8)
		0x88, 0x49, // c.lw x10, 16(x11)
		0x00, 0x36, // c.fld f8, 40(x12)
		0x67, 0x80, 0x00, 0x00, // jalr x0, 0(x1)
	}
	if !bytes.Equal(code, want) {
		t.Errorf("code = % x\nwant % x", code, want)
	}
}

// TestRISCV_FENCE pins the FENCE encoding: the toolchain expands the bare
// mnemonic to fence iorw, iorw (0x0FF0000F), not fence 0,0.
func TestRISCV_FENCE(t *testing.T) {
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·fence(SB), NOSPLIT, $0
	FENCE
	RET
`)
	code := assembleRISCVHelper(t, fn)
	want := []byte{
		0x0f, 0x00, 0xf0, 0x0f, // fence iorw, iorw
		0x67, 0x80, 0x00, 0x00, // jalr x0, 0(x1)
	}
	if !bytes.Equal(code, want) {
		t.Errorf("code = % x\nwant % x", code, want)
	}
}

// TestRISCV_RVC_WidthSpellings pins the compression of the GOROOT width
// spellings: MOVW and MOVD lower to their base load/store and compress
// exactly like LW/SW/FLD/FSD would (the toolchain compresses these shapes;
// before the normalisation they stayed 4 bytes).
func TestRISCV_RVC_WidthSpellings(t *testing.T) {
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·widths(SB), NOSPLIT, $0-16
	MOVW w+0(FP), X9
	MOVW X9, v+4(FP)
	MOVD d+0(FP), F8
	MOVD F8, r+8(FP)
	RET
`)
	code := assembleRISCVHelper(t, fn)
	want := []byte{
		0xa2, 0x44, // c.lwsp x9, 8
		0x26, 0xc6, // c.swsp x9, 12
		0x22, 0x24, // c.fldsp f8, 8
		0x22, 0xa8, // c.fsdsp f8, 16
		0x67, 0x80, 0x00, 0x00, // jalr x0, 0(x1)
	}
	if !bytes.Equal(code, want) {
		t.Errorf("code = % x\nwant % x", code, want)
	}
}

func TestRISCV_system_instrs(t *testing.T) {
	// Test FENCE, ECALL, EBREAK encoding.
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·sys(SB), NOSPLIT, $0
	FENCE
	ECALL
	EBREAK
	RET
`)
	code := assembleRISCVHelper(t, fn)
	// FENCE(4) + ECALL(4) + C.EBREAK(2) + JALR(4) = 14
	if len(code) != 14 {
		t.Errorf("expected 14 bytes, got %d (% x)", len(code), code)
	}
}

func TestRISCV_MOV_sym_FP_error(t *testing.T) {
	// MOV $sym(FP), rd should return an error (unsupported).
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·badfp(SB), NOSPLIT, $0
	MOV $arg(FP), X10
	RET
`)
	_, _, _, _, _, err := assembleRISCV(fn)
	if err == nil {
		t.Error("expected error for MOV $arg(FP), got nil")
	}
}

func TestRISCV_CALL(t *testing.T) {
	// CALL sym(SB) → JAL X1, sym(SB) with a single R_RISCV_JAL relocation.
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·calltest(SB), NOSPLIT, $0
	CALL ext(SB)
	RET
`)
	code, _, relocs, _, _, err := assembleRISCV(fn)
	if err != nil {
		t.Fatalf("assemble: %v", err)
	}
	// prologue (8) + JAL (4) + epilogue+JALR (8) = 20
	if len(code) != 20 {
		t.Fatalf("expected 20 bytes with CALL sym(SB), got %d", len(code))
	}
	if len(relocs) != 1 {
		t.Fatalf("relocs = %d, want 1", len(relocs))
	}
	r := relocs[0]
	if r.Kind != RelRISCVJal || r.Name != "ext" || r.Off != 8 || r.After != 12 || r.Addend != 0 {
		t.Errorf("reloc = {kind %v off %d after %d name %q addend %d}", r.Kind, r.Off, r.After, r.Name, r.Addend)
	}
	// The JAL instruction itself is JAL X1, 0 at function offset 8.
	wantJAL := wordLE(riscvJType(1, 0))
	if !bytes.Equal(code[8:12], wantJAL) {
		t.Errorf("JAL = % x, want % x", code[8:12], wantJAL)
	}
}

func TestRISCV_CALL_local_error(t *testing.T) {
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·calllocal(SB), NOSPLIT, $0
	CALL sub
sub:
	RET
`)
	_, _, _, _, _, err := assembleRISCV(fn)
	if err == nil {
		t.Error("expected error for CALL to local label, got nil")
	}
}

// TestRISCVIndirectBranch pins the indirect branch encodings: JMP (X5) is the
// toolchain's JALR X0, 0(X5), and the trampoline form JALR rd, offset(rs1)
// takes its destination from the first operand (regression: the base
// register was once read as the destination, silently jumping to X0).
func TestRISCVIndirectBranch(t *testing.T) {
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·f(SB), NOSPLIT, $0-0
	JMP (X5)
	JALR X0, 0(X6)
	JALR X28, 0(X9)
	RET
`)
	code := assembleRISCVHelper(t, fn)
	wantWords(t, code,
		0x00028067, // jalr x0, 5(x0), 0
		0x00030067, // jalr x0, 6(x0), 0
		0x00048e67, // jalr x28, 9(x0), 0
		0x00008067, // jalr x0, 1(x0), 0 (RET)
	)
}

// encodeOneInstrRISCV encodes a single parsed instruction against a synthetic
// offsets map, the smallest honest harness for the branch-range diagnostics:
// the spans are far larger than any source a test would want to spell out.
func encodeOneInstrRISCV(t *testing.T, src string, pc int, offsets map[string]int) ([]byte, error) {
	t.Helper()
	fn := firstTextRISCV(t, "#include \"textflag.h\"\n"+src)
	instr := fn.Body[0].(*ast.Instr)
	return encodeRISCVInstr(instr, pc, offsets, riscvFrameInfo{}, nil, nil)
}

// TestRISCVBranchJumpRange checks that displacements beyond the B-type span
// [-4096, 4094] and the J-type span [-1048576, 1048574] are diagnosed instead
// of wrapping silently to a wrong target.
func TestRISCVBranchJumpRange(t *testing.T) {
	cases := []struct {
		name string
		src  string
		off  int // the target's function-relative offset (pc 0)
		ok   bool
	}{
		{"branch max", "BEQ X10, X11, tgt\nRET\n", 4094, true},
		{"branch past max", "BEQ X10, X11, tgt\nRET\n", 4096, false},
		{"branch back max", "BEQ X10, X11, tgt\nRET\n", -4096, true},
		{"branch back past max", "BEQ X10, X11, tgt\nRET\n", -4098, false},
		{"branchz past max", "BEQZ X10, tgt\nRET\n", 4096, false},
		{"jump max", "JMP tgt\nRET\n", 1048574, true},
		{"jump past max", "JMP tgt\nRET\n", 1048576, false},
		{"jump back max", "JMP tgt\nRET\n", -1048576, true},
		{"jump back past max", "JMP tgt\nRET\n", -1048578, false},
		{"jal past max", "JAL tgt\nRET\n", 1048576, false},
	}
	for _, c := range cases {
		t.Run(c.name, func(t *testing.T) {
			_, err := encodeOneInstrRISCV(t, "TEXT ·f(SB), NOSPLIT, $0\n\t"+c.src, 0, map[string]int{"tgt": c.off})
			if c.ok && err != nil {
				t.Fatalf("unexpected error: %v", err)
			}
			if !c.ok && err == nil {
				t.Fatal("expected an out-of-range diagnostic, got none")
			}
		})
	}
}

// TestRISCVBranchFarBody drives the relaxation pass through the full
// assembler: a forward branch over a body larger than the B-type span is
// rewritten as an inverted branch over an inserted JMP, the same layout the
// toolchain produces, instead of wrapping to a wrong target.
func TestRISCVBranchFarBody(t *testing.T) {
	var sb strings.Builder
	sb.WriteString("#include \"textflag.h\"\nTEXT ·far(SB), NOSPLIT, $0\n\tBEQ X10, X11, done\n")
	for range 1100 {
		sb.WriteString("\tADD X10, X11, X12\n")
	}
	sb.WriteString("done:\n\tRET\n")
	fn := firstTextRISCV(t, sb.String())
	out, _, _, _, _, err := assembleRISCV(fn)
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	// The relaxed branch at offset 0 targets the inserted JMP at 4 (bne
	// x10, x11, +4); the JMP at 4 carries the far forward displacement.
	wantBranch := wordLE(riscvBType(riscvEnc{0x63, 0x1, 0x00}, 10, 11, 4))
	if !bytes.Equal(out[0:4], wantBranch) {
		t.Errorf("relaxed branch = %x, want %x", out[0:4], wantBranch)
	}
	// done sits after 1100 ADDs: 4 + 4400, i.e. offset 4404 from the JMP at 4.
	wantJmp := wordLE(riscvJType(0, 4404))
	if !bytes.Equal(out[4:8], wantJmp) {
		t.Errorf("inserted JMP = %x, want %x", out[4:8], wantJmp)
	}
}

// TestRISCV_CSRRange checks the CSR address range: the 12-bit field is
// diagnosed rather than masked, so CSRRW $4096 does not silently address
// CSR 0.
func TestRISCV_CSRRange(t *testing.T) {
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·csrhi(SB), NOSPLIT, $0
	CSRRW $4096, X10, X11
	RET
`)
	if _, _, _, _, _, err := assembleRISCV(fn); err == nil {
		t.Error("expected an out-of-range error for CSR $4096, got none")
	}
	fn = firstTextRISCV(t, `#include "textflag.h"
TEXT ·csrmax(SB), NOSPLIT, $0
	CSRRW $4095, X10, X11
	RET
`)
	if _, _, _, _, _, err := assembleRISCV(fn); err != nil {
		t.Errorf("CSR $4095 must assemble: %v", err)
	}
}

// TestRISCV_Imm64Rejected checks that immediates outside the signed 32-bit
// span are diagnosed instead of silently truncated to their low 32 bits (the
// toolchain materialises such constants via SLLI expansion, which this
// assembler does not implement).
func TestRISCV_Imm64Rejected(t *testing.T) {
	cases := []string{
		"MOV $0x123456789, X10",
		"ADDI $0x100000000, X10, X11",
		"ANDI $-0x800000001, X10, X11",
		"SUB $0x100000000, X10, X11",
	}
	for _, src := range cases {
		fn := firstTextRISCV(t, "#include \"textflag.h\"\nTEXT ·wide(SB), NOSPLIT, $0\n\t"+src+"\n\tRET\n")
		if _, _, _, _, _, err := assembleRISCV(fn); err == nil {
			t.Errorf("%s: expected an out-of-range error, got none", src)
		}
	}
	// The full signed 32-bit span still assembles, including the SUB form
	// whose negated immediate only just fits.
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·edge(SB), NOSPLIT, $0
	MOV  $2147483647, X10
	MOV  $-2147483648, X11
	SUB  $0x80000000, X12, X13
	RET
`)
	if _, _, _, _, _, err := assembleRISCV(fn); err != nil {
		t.Errorf("int32-span immediates must assemble: %v", err)
	}
}

// riscvWants decodes code as little-endian words and pins each one; the
// expected values below were read off GOARCH=riscv64 go tool objdump of
// kernels assembled with go tool asm (the toolchain's riscv64.s testdata
// cross-checks the same words).
func riscvWants(t *testing.T, code []byte, want ...uint32) {
	t.Helper()
	got := make([]uint32, 0, len(code)/4)
	for i := 0; i+4 <= len(code); i += 4 {
		got = append(got, binary.LittleEndian.Uint32(code[i:]))
	}
	if len(got) < len(want) {
		t.Fatalf("word count = %d, want %d\ncode: % x", len(got), len(want), code)
	}
	// The RET (JALR) ends the sequence; only the pinned prefix is compared.
	for i := range want {
		if got[i] != want[i] {
			t.Errorf("word %d = %08x, want %08x", i, got[i], want[i])
		}
	}
}

// riscvWantsHex pins the exact hex encoding of a function's instruction
// bytes, including any 2-byte compressed instructions in the stream; the
// expected strings were read off GOARCH=riscv64 go tool objdump of kernels
// assembled with go tool asm (the toolchain's riscv64.s testdata
// cross-checks the same words).
func riscvWantsHex(t *testing.T, code []byte, wantHex string) {
	t.Helper()
	got := hex.EncodeToString(code)
	if got != wantHex {
		t.Errorf("code = %s, want %s", got, wantHex)
	}
}

// TestRISCV_extendedPseudos pins the toolchain-synthesised instructions:
// ANDN/ORN (XORI + AND/OR through the destination or TMP), the five-word
// MIN/MAX expansion, the four-word rotate, ROR's compressed reverse shift
// (C.SLLI when rd == rs1, both non-zero, 1 <= sll <= 63), the identical-
// input MIN/MAX fold to C.MV, FABSD (FSGNJX.D), SEQZ and RDTIME (csrrs with
// the time CSR).
func TestRISCV_extendedPseudos(t *testing.T) {
	t.Run("logic and minmax", func(t *testing.T) {
		fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·l(SB), NOSPLIT, $0
	ANDN X19, X20, X21
	ANDN X19, X20
	ORN X20, X19
	MAX X26, X28, X29
	MIN X29, X30, X5
	MAX X5, X5
	MAX X5, X5, X6
	SEQZ X5, X6
	NEG X5, X6
	NOT X5
	RDTIME X5
	RET
`)
		code := assembleRISCVHelper(t, fn)
		// Words 0-10 up to the folded C.MV pair (halfwords 96 82 and 16 83),
		// then SEQZ, NEG, NOT and RDTIME.
		riscvWantsHex(t, code,
			"93caf9ffb37a5a01"+"93cff9ff337afa01"+"934ffaffb3e9f901"+
				"b32fae01b30ff041b34eae01b3fedf01b34ede01"+
				"b3afee01b30ff041b342df01b3f25f00b3425f00"+
				"9682"+"1683"+
				"13b31200"+"33035040"+"93c2f2ff"+"f32210c0"+"67800000")
	})

	t.Run("rotate", func(t *testing.T) {
		fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·r(SB), NOSPLIT, $0
	ROR X10, X11, X12
	ROR X10, X11
	ROR $63, X11
	RORIW $31, X13, X14
	RORIW $1, X14, X15
	RORIW $3, X14
	RORW X15, X16, X17
	RORW $31, X13
	RET
`)
		code := assembleRISCVHelper(t, fn)
		// The third ROR carries the compressed C.SLLI (05 86) in mid-stream.
		riscvWantsHex(t, code,
			"b30fa040b39ff50133d6a50033e6cf00"+
				"b30fa040b39ff501b3d5a500b3e5bf00"+
				"93dff5038605b3e5bf00"+
				"9bdff6011b97160033e7ef00"+
				"9b5f17009b17f701b3e7ff00"+
				"9b5f37001b17d70133e7ef00"+
				"b30ff040bb1ff801bb58f800b3e81f01"+
				"9bdff6019b961600b3e6df00"+"67800000")
	})

	t.Run("fp and branches", func(t *testing.T) {
		fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·f(SB), NOSPLIT, $0
	FABSD F1, F2
	FSGNJD F1, F0, F2
	FMADDD F1, F2, F3, F4
	FMSUBD F1, F2, F3, F4
	FNMSUBD F1, F2, F3, F4
	BGT X5, X6, tgt
	BLE X5, X6, tgt
	BGTU X5, X6, tgt
	BLEU X5, X6, tgt
tgt:
	RDTIME X5
	RET
`)
		code := assembleRISCVHelper(t, fn)
		riscvWantsHex(t, code,
			"53a11022"+"53011022"+"4382201a4782201a4b82201a"+
				"63485300635653006364530063725300"+ // blt/bge/bltu/bgeu x6, x5
				"f32210c0"+"67800000")
	})
}

// TestRISCV_amoWords pins the full AMO family: every AMO carries aq and rl
// (funct7 |= 3), LR is acquire (funct7 |= 2) and SC release (funct7 |= 1),
// exactly as GOARCH=riscv64 go tool asm encodes them.
func TestRISCV_amoWords(t *testing.T) {
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·amo(SB), NOSPLIT, $0
	AMOSWAPW X5, (X6), X7
	AMOSWAPD X5, (X6), X7
	AMOADDW X5, (X6), X7
	AMOADDD X5, (X6), X7
	AMOANDW X5, (X6), X7
	AMOANDD X5, (X6), X7
	AMOORW X5, (X6), X7
	AMOORD X5, (X6), X7
	AMOXORW X5, (X6), X7
	AMOXORD X5, (X6), X7
	AMOMAXW X5, (X6), X7
	AMOMAXD X5, (X6), X7
	AMOMAXUW X5, (X6), X7
	AMOMAXUD X5, (X6), X7
	AMOMINUW X5, (X6), X7
	AMOMINUD X5, (X6), X7
	LRW (X5), X6
	LRD (X5), X6
	SCW X5, (X6), X7
	SCD X5, (X6), X7
	RET
`)
	code := assembleRISCVHelper(t, fn)
	riscvWants(t, code,
		0x0E5323AF, // amoswap.w
		0x0E5333AF, // amoswap.d
		0x065323AF, // amoaddd.w
		0x065333AF, // amoadd.d
		0x665323AF, // amoand.w
		0x665333AF, // amoand.d
		0x465323AF, // amoor.w
		0x465333AF, // amoor.d
		0x265323AF, // amoxor.w
		0x265333AF, // amoxor.d
		0xA65323AF, // amomax.w
		0xA65333AF, // amomax.d
		0xE65323AF, // amomaxu.w
		0xE65333AF, // amomaxu.d
		0xC65323AF, // amominu.w
		0xC65333AF, // amominu.d
		0x1402A32F, // lr.w (aq)
		0x1402B32F, // lr.d
		0x1A5323AF, // sc.w (rl)
		0x1A5333AF, // sc.d
	)
}

// TestRISCV_vectorWords pins the RVV slice and the VSET* encodings.  The
// toolchain canonicalises an immediate avl to vsetivli even under the
// VSETVLI spelling (`VSETVLI $15` and `VSETIVLI $15` come out byte-
// identical), which is what the 0xC00 bit of the first word carries.
func TestRISCV_vectorWords(t *testing.T) {
	fn := firstTextRISCV(t, `#include "textflag.h"
TEXT ·v(SB), NOSPLIT, $0
	VSETVLI X5, E8, M8, TA, MA, X6
	VSETIVLI $4, E32, M1, TA, MA, X0
	VSETVLI $15, E32, M1, TA, MA, X12
	VADDVV V1, V2, V3
	VADDVX X12, V12, V12
	VXORVV V8, V16, V24
	VMSEQVX X12, V8, V0
	VMSNEVV V8, V16, V0
	VSLLVI $8, V28, V30
	VSRLVI $25, V29, V29
	VFIRSTM V0, X6
	VIDV V12
	VMV4RV V8, V24
	VLE8V (X10), V8
	VSE8V V24, (X10)
	VSE32V V9, (X11)
	VLSSEG4E32V (X14), X0, V0
	VLSSEG8E32V (X10), X0, V4
	RET
`)
	code := assembleRISCVHelper(t, fn)
	riscvWants(t, code,
		0x0C32F357, // vsetvli x6, x5, vtype 0xc3 (E8, M8, TA, MA)
		0xCD027057, // vsetivli x0, 4
		0xCD07F657, // vsetivli x12, 15: VSETVLI $15 canonicalises to the same word
		0x022081D7, // vadd.vv v3, v2, v1
		0x02C64657, // vadd.vx v12, v12, x12
		0x2F040C57, // vxor.vv v24, v16, v8
		0x62864057, // vmseq.vx v0, v8, x12
		0x67040057, // vmsne.vv v0, v16, v8
		0x97C43F57, // vsll.vi v30, v28, 8
		0xA3DCBED7, // vsrl.vi v29, v29, 25
		0x4208A357, // vmfirst.m x6, v0
		0x5208A657, // vid.v v12
		0x9E81BC57, // vmv4r.v v24, v8
		0x02050407, // vle8.v v8, (x10)
		0x02050C27, // vse8.v v24, (x10)
		0x0205E4A7, // vse32.v v9, (x11)
		0x6A076007, // vlsseg4e32.v v0, (x14), x0
		0xEA056207, // vlsseg8e32.v v4, (x10), x0
	)
}