reg: rename Bytes() to Size() (#74)

It was pointed out #73 that Bytes() is a poor name for the size of the register in bytes. In idiomatic Go you would probably expect a Bytes() method to return []byte.

This diff changes the Bytes() to Size(). As a result the Size type also needed to be renamed, and Width seemed a reasonable choice.

Fixes #73

reg/collection.go

@@ -13,11 +13,11 @@ func NewCollection() *Collection {
 	}
 }
 
-// VirtualRegister allocates and returns a new virtual register of the given kind and size.
-func (c *Collection) VirtualRegister(k Kind, s Size) Virtual {
+// VirtualRegister allocates and returns a new virtual register of the given kind and width.
+func (c *Collection) VirtualRegister(k Kind, w Width) Virtual {
 	vid := c.vid[k]
 	c.vid[k]++
-	return NewVirtual(vid, k, s)
+	return NewVirtual(vid, k, w)
 }
 
 // GP8 allocates and returns a general-purpose 8-bit register.
@@ -32,8 +32,8 @@ func (c *Collection) GP32() GPVirtual { return c.GP(B32) }
 // GP64 allocates and returns a general-purpose 64-bit register.
 func (c *Collection) GP64() GPVirtual { return c.GP(B64) }
 
-// GP allocates and returns a general-purpose register of the given size.
-func (c *Collection) GP(s Size) GPVirtual { return newgpv(c.VirtualRegister(KindGP, s)) }
+// GP allocates and returns a general-purpose register of the given width.
+func (c *Collection) GP(w Width) GPVirtual { return newgpv(c.VirtualRegister(KindGP, w)) }
 
 // XMM allocates and returns a 128-bit vector register.
 func (c *Collection) XMM() VecVirtual { return c.Vec(B128) }
@@ -44,5 +44,5 @@ func (c *Collection) YMM() VecVirtual { return c.Vec(B256) }
 // ZMM allocates and returns a 512-bit vector register.
 func (c *Collection) ZMM() VecVirtual { return c.Vec(B512) }
 
-// Vec allocates and returns a vector register of the given size.
-func (c *Collection) Vec(s Size) VecVirtual { return newvecv(c.VirtualRegister(KindVector, s)) }
+// Vec allocates and returns a vector register of the given width.
+func (c *Collection) Vec(w Width) VecVirtual { return newvecv(c.VirtualRegister(KindVector, w)) }

reg/reg_test.go

@@ -2,10 +2,10 @@ package reg
 
 import "testing"
 
-func TestSpecBytes(t *testing.T) {
+func TestSpecSize(t *testing.T) {
 	cases := []struct {
-		Spec  Spec
-		Bytes uint
+		Spec Spec
+		Size uint
 	}{
 		{S0, 0},
 		{S8L, 1},
@@ -18,8 +18,8 @@ func TestSpecBytes(t *testing.T) {
 		{S512, 64},
 	}
 	for _, c := range cases {
-		if c.Spec.Bytes() != c.Bytes {
-			t.Errorf("%v.Bytes() = %d; expect = %d", c.Spec, c.Spec.Bytes(), c.Bytes)
+		if c.Spec.Size() != c.Size {
+			t.Errorf("%v.Size() = %d; expect = %d", c.Spec, c.Spec.Size(), c.Size)
 		}
 	}
 }

reg/types.go

@@ -5,12 +5,12 @@ import (
 	"fmt"
 )
 
-// Size is a register size.
-type Size uint
+// Width is a register width.
+type Width uint
 
-// Typical register sizes.
+// Typical register width values.
 const (
-	B8 Size = 1 << iota
+	B8 Width = 1 << iota
 	B16
 	B32
 	B64
@@ -19,8 +19,8 @@ const (
 	B512
 )
 
-// Bytes returns the register size in bytes.
-func (s Size) Bytes() uint { return uint(s) }
+// Size returns the register width in bytes.
+func (w Width) Size() uint { return uint(w) }
 
 // Kind is a class of registers.
 type Kind uint8
@@ -47,8 +47,8 @@ func (f *Family) add(r Physical) {
 }
 
 // Virtual returns a virtual register from this family's kind.
-func (f *Family) Virtual(id VID, s Size) Virtual {
-	return NewVirtual(id, f.Kind, s)
+func (f *Family) Virtual(id VID, w Width) Virtual {
+	return NewVirtual(id, f.Kind, w)
 }
 
 // Registers returns the registers in this family.
@@ -78,7 +78,7 @@ func (f *Family) Lookup(id PID, s Spec) Physical {
 // Register represents a virtual or physical register.
 type Register interface {
 	Kind() Kind
-	Bytes() uint
+	Size() uint
 	Asm() string
 	as(Spec) Register
 	register()
@@ -105,16 +105,16 @@ func ToVirtual(r Register) Virtual {
 type virtual struct {
 	id   VID
 	kind Kind
-	Size
+	Width
 	mask uint16
 }
 
 // NewVirtual builds a Virtual register.
-func NewVirtual(id VID, k Kind, s Size) Virtual {
+func NewVirtual(id VID, k Kind, w Width) Virtual {
 	return virtual{
-		id:   id,
-		kind: k,
-		Size: s,
+		id:    id,
+		kind:  k,
+		Width: w,
 	}
 }
 
@@ -123,19 +123,19 @@ func (v virtual) Kind() Kind     { return v.kind }
 
 func (v virtual) Asm() string {
 	// TODO(mbm): decide on virtual register syntax
-	return fmt.Sprintf("<virtual:%v:%v:%v>", v.id, v.Kind(), v.Bytes())
+	return fmt.Sprintf("<virtual:%v:%v:%v>", v.id, v.Kind(), v.Size())
 }
 
 func (v virtual) SatisfiedBy(p Physical) bool {
-	return v.Kind() == p.Kind() && v.Bytes() == p.Bytes() && (v.mask == 0 || v.mask == p.Mask())
+	return v.Kind() == p.Kind() && v.Size() == p.Size() && (v.mask == 0 || v.mask == p.Mask())
 }
 
 func (v virtual) as(s Spec) Register {
 	return virtual{
-		id:   v.id,
-		kind: v.kind,
-		Size: Size(s.Bytes()),
-		mask: s.Mask(),
+		id:    v.id,
+		kind:  v.kind,
+		Width: Width(s.Size()),
+		mask:  s.Mask(),
 	}
 }
 
@@ -229,8 +229,8 @@ func (s Spec) Mask() uint16 {
 	return uint16(s)
 }
 
-// Bytes returns the register size in bytes.
-func (s Spec) Bytes() uint {
+// Size returns the register width in bytes.
+func (s Spec) Size() uint {
 	x := uint(s)
 	return (x >> 1) + (x & 1)
 }