--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/asm/AJBaseReg.st	Tue Dec 15 23:18:02 2015 +0000
@@ -0,0 +1,129 @@
+"{ Package: 'jv:dragonfly/asm' }"
+
+"{ NameSpace: Smalltalk }"
+
+AJOperand subclass:#AJBaseReg
+	instanceVariableNames:'size code name'
+	classVariableNames:''
+	poolDictionaries:''
+	category:'AsmJit-Operands'
+!
+
+AJBaseReg comment:'AJBaseReg  -- abstract superclass of all register operands.

Instance Variables:
	size	<Number>  Width in bytes (1, 2, 4, 8...)
	code	<Integer>  Non-negative integer, encoding varies with subclass. For AJx86GPRegisters, ten bits: xyttttnnnn
						where nnnn is the register number 0-15, tttt is the "type", which encodes size as a power of 2. 
						Higher types are used in other subclasses.
						If y is 1, REX prefix is required to encode this register.
						If x is 1, this register cannot be used when any REX prefix is present in the instruction.
	name	<Symbol>  Name by which this register may be referenced in instructions'
+!
+
+!AJBaseReg class methodsFor:'instance creation'!
+
+code: aRegisterCode name: aSymbol
+    ^ self basicNew initializeWithCode: aRegisterCode name: aSymbol
+! !
+
+!AJBaseReg methodsFor:'accessing'!
+
+annotation: anObject
+    "registers gereally are used as single instances, hence putting
+    an annotation on the default register will change the annotation
+    for all the users. To avoid that, the receiver is copied first"
+    ^ self copy
+        basicAnnotation: anObject;
+        yourself
+!
+
+code
+    "Answer the value of code"
+
+    ^ code
+!
+
+code: anObject
+    "Set the value of code"
+
+    code := anObject
+!
+
+description
+    ^ String streamContents: [ :s | self descriptionOn: s ].
+!
+
+index
+    ^ code bitAnd: RegCodeMask
+!
+
+influencingRegisters
+    ^ #()
+!
+
+name
+    ^ name
+!
+
+size
+    ^ size
+!
+
+type
+    ^ code bitAnd: RegTypeMask
+! !
+
+!AJBaseReg methodsFor:'comparing'!
+
+= otherReg
+
+    ^ (self class == otherReg class) and: [ code = otherReg code ]
+!
+
+hash
+    ^ code hash
+! !
+
+!AJBaseReg methodsFor:'initialize-release'!
+
+initializeWithCode: aRegisterCode name: aSymbol
+    super initialize.
+    self code: aRegisterCode.	"Also sets size"
+    name := aSymbol
+! !
+
+!AJBaseReg methodsFor:'printing'!
+
+descriptionOn: aStream
+    self subclassResponsibility
+! !
+
+!AJBaseReg methodsFor:'private'!
+
+basicAnnotation: anObject
+    "private setter"
+    annotation := anObject
+! !
+
+!AJBaseReg methodsFor:'testing'!
+
+isGeneralPurpose
+    self subclassResponsibility 
+!
+
+isUpperBank
+    "Used for emitting the REX Prefix Byte on 64bit machines"
+    ^ self index > 7
+!
+
+isX86
+    self subclassResponsibility
+!
+
+prohibitsRex
+    "Answer true if this register cannot be used in any instruction that has a REX prefix.
+    Of the general-purpose registers, this is true only of SPL, BPL, SIL, DIL."
+
+    ^ (code & RegProhibitsRexMask) ~~ 0
+!
+
+requiresRex 
+    "Answer true if use of this register requires that the instruction have a REX prefix.
+    This can be because the register cannot be accessed except with REX (high bank or 64-only low byte)
+    or because the register is 64-bits wide"
+    
+    ^(code & RegRequiresRexMask) ~~ 0
+! !
+