Implemented register push and pop

src/build/arch/x64/Pop.go

@@ -0,0 +1,16 @@
+package x64
+
+import "git.akyoto.dev/cli/q/src/build/cpu"
+
+// PopReg pops a value from the stack and saves it into the register.
+func PopReg(code []byte, register cpu.Register) []byte {
+	if register >= 8 {
+		code = append(code, REX(0, 0, 0, 1))
+		register -= 8
+	}
+
+	return append(
+		code,
+		0x58+byte(register),
+	)
+}

src/build/arch/x64/Pop_test.go

@@ -0,0 +1,39 @@
+package x64_test
+
+import (
+	"testing"
+
+	"git.akyoto.dev/cli/q/src/build/arch/x64"
+	"git.akyoto.dev/cli/q/src/build/cpu"
+	"git.akyoto.dev/go/assert"
+)
+
+func TestPopRegister(t *testing.T) {
+	usagePatterns := []struct {
+		Register cpu.Register
+		Code     []byte
+	}{
+		{x64.RAX, []byte{0x58}},
+		{x64.RCX, []byte{0x59}},
+		{x64.RDX, []byte{0x5A}},
+		{x64.RBX, []byte{0x5B}},
+		{x64.RSP, []byte{0x5C}},
+		{x64.RBP, []byte{0x5D}},
+		{x64.RSI, []byte{0x5E}},
+		{x64.RDI, []byte{0x5F}},
+		{x64.R8, []byte{0x41, 0x58}},
+		{x64.R9, []byte{0x41, 0x59}},
+		{x64.R10, []byte{0x41, 0x5A}},
+		{x64.R11, []byte{0x41, 0x5B}},
+		{x64.R12, []byte{0x41, 0x5C}},
+		{x64.R13, []byte{0x41, 0x5D}},
+		{x64.R14, []byte{0x41, 0x5E}},
+		{x64.R15, []byte{0x41, 0x5F}},
+	}
+
+	for _, pattern := range usagePatterns {
+		t.Logf("pop %s", pattern.Register)
+		code := x64.PopReg(nil, pattern.Register)
+		assert.DeepEqual(t, code, pattern.Code)
+	}
+}

src/build/arch/x64/Push.go

@@ -0,0 +1,16 @@
+package x64
+
+import "git.akyoto.dev/cli/q/src/build/cpu"
+
+// PushReg pushes the value inside the register onto the stack.
+func PushReg(code []byte, register cpu.Register) []byte {
+	if register >= 8 {
+		code = append(code, REX(0, 0, 0, 1))
+		register -= 8
+	}
+
+	return append(
+		code,
+		0x50+byte(register),
+	)
+}

src/build/arch/x64/Push_test.go

@@ -0,0 +1,39 @@
+package x64_test
+
+import (
+	"testing"
+
+	"git.akyoto.dev/cli/q/src/build/arch/x64"
+	"git.akyoto.dev/cli/q/src/build/cpu"
+	"git.akyoto.dev/go/assert"
+)
+
+func TestPushRegister(t *testing.T) {
+	usagePatterns := []struct {
+		Register cpu.Register
+		Code     []byte
+	}{
+		{x64.RAX, []byte{0x50}},
+		{x64.RCX, []byte{0x51}},
+		{x64.RDX, []byte{0x52}},
+		{x64.RBX, []byte{0x53}},
+		{x64.RSP, []byte{0x54}},
+		{x64.RBP, []byte{0x55}},
+		{x64.RSI, []byte{0x56}},
+		{x64.RDI, []byte{0x57}},
+		{x64.R8, []byte{0x41, 0x50}},
+		{x64.R9, []byte{0x41, 0x51}},
+		{x64.R10, []byte{0x41, 0x52}},
+		{x64.R11, []byte{0x41, 0x53}},
+		{x64.R12, []byte{0x41, 0x54}},
+		{x64.R13, []byte{0x41, 0x55}},
+		{x64.R14, []byte{0x41, 0x56}},
+		{x64.R15, []byte{0x41, 0x57}},
+	}
+
+	for _, pattern := range usagePatterns {
+		t.Logf("push %s", pattern.Register)
+		code := x64.PushReg(nil, pattern.Register)
+		assert.DeepEqual(t, code, pattern.Code)
+	}
+}