gasm-sdk/disasm/naming_amd64_test.go

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

package disasm

import (
	"testing"

	"sourcedock.dev/petrbalvin/gasm-sdk/arch"
)

// TestDegenerateNaming pins the supplementary naming table over the whole
// set of encodings the Go toolchain's assembler corpus carries for the
// families x/arch decodes to the degenerate zero instruction.  Every row's
// bytes are the corpus's own expected-encoding comments (machine-checked
// by the toolchain's assembler test suite); every text is the corpus's own
// spelling of the instruction.
//
// The rows whose text the encoder carries are also in
// testdata/parity_amd64_unlisted.txt, where the parity and round-trip
// tests pin them; this table covers them too so a fixture edit cannot
// move one without this one noticing.  ENDBR32 is the exception: the
// toolchain knows no spelling for it (its obj/x86 table carries ENDBR64
// only), so its text is pinned here as bytes and text, with no
// round-trip.
func TestDegenerateNaming(t *testing.T) {
	for _, tt := range []struct {
		code []byte
		text string
	}{
		// amd64enc.s: ADCXL (BX), DX // 660f38f613 and kin.
		{[]byte{0x66, 0x0f, 0x38, 0xf6, 0x13}, "ADCXL 0(BX), DX"},
		{[]byte{0x66, 0x41, 0x0f, 0x38, 0xf6, 0x13}, "ADCXL 0(R11), DX"},
		{[]byte{0x66, 0x0f, 0x38, 0xf6, 0xd2}, "ADCXL DX, DX"},
		{[]byte{0x66, 0x41, 0x0f, 0x38, 0xf6, 0xd3}, "ADCXL R11, DX"},
		{[]byte{0x66, 0x44, 0x0f, 0x38, 0xf6, 0x1b}, "ADCXL 0(BX), R11"},
		{[]byte{0x66, 0x45, 0x0f, 0x38, 0xf6, 0x1b}, "ADCXL 0(R11), R11"},
		{[]byte{0x66, 0x44, 0x0f, 0x38, 0xf6, 0xda}, "ADCXL DX, R11"},
		{[]byte{0x66, 0x45, 0x0f, 0x38, 0xf6, 0xdb}, "ADCXL R11, R11"},
		{[]byte{0x66, 0x48, 0x0f, 0x38, 0xf6, 0x13}, "ADCXQ 0(BX), DX"},
		{[]byte{0x66, 0x49, 0x0f, 0x38, 0xf6, 0x13}, "ADCXQ 0(R11), DX"},
		{[]byte{0x66, 0x48, 0x0f, 0x38, 0xf6, 0xd2}, "ADCXQ DX, DX"},
		{[]byte{0x66, 0x49, 0x0f, 0x38, 0xf6, 0xd3}, "ADCXQ R11, DX"},
		{[]byte{0x66, 0x4c, 0x0f, 0x38, 0xf6, 0x1b}, "ADCXQ 0(BX), R11"},
		{[]byte{0x66, 0x4d, 0x0f, 0x38, 0xf6, 0x1b}, "ADCXQ 0(R11), R11"},
		{[]byte{0x66, 0x4c, 0x0f, 0x38, 0xf6, 0xda}, "ADCXQ DX, R11"},
		{[]byte{0x66, 0x4d, 0x0f, 0x38, 0xf6, 0xdb}, "ADCXQ R11, R11"},
		// amd64enc.s: ADOXL (BX), DX // f30f38f613 and kin.
		{[]byte{0xf3, 0x0f, 0x38, 0xf6, 0x13}, "ADOXL 0(BX), DX"},
		{[]byte{0xf3, 0x41, 0x0f, 0x38, 0xf6, 0x13}, "ADOXL 0(R11), DX"},
		{[]byte{0xf3, 0x0f, 0x38, 0xf6, 0xd2}, "ADOXL DX, DX"},
		{[]byte{0xf3, 0x41, 0x0f, 0x38, 0xf6, 0xd3}, "ADOXL R11, DX"},
		{[]byte{0xf3, 0x44, 0x0f, 0x38, 0xf6, 0x1b}, "ADOXL 0(BX), R11"},
		{[]byte{0xf3, 0x45, 0x0f, 0x38, 0xf6, 0x1b}, "ADOXL 0(R11), R11"},
		{[]byte{0xf3, 0x44, 0x0f, 0x38, 0xf6, 0xda}, "ADOXL DX, R11"},
		{[]byte{0xf3, 0x45, 0x0f, 0x38, 0xf6, 0xdb}, "ADOXL R11, R11"},
		{[]byte{0xf3, 0x48, 0x0f, 0x38, 0xf6, 0x13}, "ADOXQ 0(BX), DX"},
		{[]byte{0xf3, 0x49, 0x0f, 0x38, 0xf6, 0x13}, "ADOXQ 0(R11), DX"},
		{[]byte{0xf3, 0x48, 0x0f, 0x38, 0xf6, 0xd2}, "ADOXQ DX, DX"},
		{[]byte{0xf3, 0x49, 0x0f, 0x38, 0xf6, 0xd3}, "ADOXQ R11, DX"},
		{[]byte{0xf3, 0x4c, 0x0f, 0x38, 0xf6, 0x1b}, "ADOXQ 0(BX), R11"},
		{[]byte{0xf3, 0x4d, 0x0f, 0x38, 0xf6, 0x1b}, "ADOXQ 0(R11), R11"},
		{[]byte{0xf3, 0x4c, 0x0f, 0x38, 0xf6, 0xda}, "ADOXQ DX, R11"},
		{[]byte{0xf3, 0x4d, 0x0f, 0x38, 0xf6, 0xdb}, "ADOXQ R11, R11"},
		// amd64enc.s: RDSEEDW DX // 660fc7fa.
		{[]byte{0x66, 0x0f, 0xc7, 0xfa}, "RDSEEDW DX"},
		{[]byte{0x66, 0x41, 0x0f, 0xc7, 0xfb}, "RDSEEDW R11"},
		// amd64enc_extra.s: RDPID DX // f30fc7fa.
		{[]byte{0xf3, 0x0f, 0xc7, 0xfa}, "RDPID DX"},
		{[]byte{0xf3, 0x41, 0x0f, 0xc7, 0xfb}, "RDPID R11"},
		// amd64enc_extra.s: TPAUSE BX // 660faef3 and kin.
		{[]byte{0x66, 0x0f, 0xae, 0xf3}, "TPAUSE BX"},
		{[]byte{0xf3, 0x0f, 0xae, 0xf3}, "UMONITOR BX"},
		{[]byte{0xf2, 0x0f, 0xae, 0xf3}, "UMWAIT BX"},
		// amd64enc_extra.s: ENDBR64 // f30f1efa; ENDBR32 has no
		// toolchain spelling.
		{[]byte{0xf3, 0x0f, 0x1e, 0xfa}, "ENDBR64"},
		{[]byte{0xf3, 0x0f, 0x1e, 0xfb}, "ENDBR32"},
	} {
		ins, err := Decode(arch.AMD64, tt.code, 0)
		if err != nil {
			t.Errorf("% x: %v", tt.code, err)
			continue
		}
		if ins.Text != tt.text || ins.Len != len(tt.code) {
			t.Errorf("% x: %q (%d bytes), want %q (%d)",
				tt.code, ins.Text, ins.Len, tt.text, len(tt.code))
		}
	}
}

// TestDegenerateNamingBoundaries guards the table's edges: bytes the
// decoder rejects outright keep the placeholder, and the prefix
// combinations no toolchain spelling carries stay unnamed even where the
// decode is degenerate.  The bare 0F 38 F6 form is the 32-bit ADCX of the
// Intel manual; the toolchain's ADCXL spelling always carries the
// operand-size override, so the bare form is left to the placeholder
// rather than named to a spelling that would re-encode differently.
func TestDegenerateNamingBoundaries(t *testing.T) {
	for _, tt := range []struct {
		code []byte
		text string
	}{
		// Rejected outright: RDSEED without the operand-size override
		// (the bare 0F C7 /7 register form), MONITORX and MWAITX, the
		// hint NOP CLDEMOTE.
		{[]byte{0x0f, 0xc7, 0xfa}, "???"},
		{[]byte{0x0f, 0x01, 0xfa}, "???"},
		{[]byte{0x0f, 0x01, 0xfb}, "???"},
		{[]byte{0x0f, 0x1c, 0x03}, "???"},
		// Degenerate but outside the table's prefix gates: repne ADCX is
		// no instruction the corpus names.
		{[]byte{0xf2, 0x0f, 0x38, 0xf6, 0xd2}, "REPNE; Op(0)"},
		// MONITOR and MWAIT decode as named opcodes and never reach the
		// table.
		{[]byte{0x0f, 0x01, 0xc8}, "MONITOR"},
		{[]byte{0x0f, 0x01, 0xc9}, "MWAIT"},
	} {
		ins, err := Decode(arch.AMD64, tt.code, 0)
		if err != nil {
			t.Errorf("% x: %v", tt.code, err)
			continue
		}
		if ins.Text != tt.text {
			t.Errorf("% x: %q, want %q", tt.code, ins.Text, tt.text)
		}
	}
}