Restore validation. Fix offset validation directly in the backend.

smalltalksrc/VMMaker/CogAbstractInstruction.class.st

@@ -1228,9 +1228,8 @@ CogAbstractInstruction >> isPCDependent [
 
 { #category : #testing }
 CogAbstractInstruction >> isWithinMwOffsetRange: anAddress [
-	"Answer if an address can be accessed using the offset in a MoveMw:r:R: or similar instruction.
-	 We assume this is true for 32-bit processors and expect 64-bit processors to answer false
-	 for values in the interpreter or the object memory."
+	"Answer if an immediate value can be used as offset in a MoveMw:r:R: or similar instruction.
+	 By default, the backend will handle it"
 
 	^true
 ]

smalltalksrc/VMMaker/CogX64Compiler.class.st

@@ -4345,14 +4345,11 @@ CogX64Compiler >> isQuick: operand [
 ]
 
 { #category : #testing }
-CogX64Compiler >> isWithinMwOffsetRange: anAddress [
-	"Answer if an address can be accessed using the offset in a MoveMw:r:R: or similar instruction.
-	 We assume this is true for 32-bit processors and expect 64-bit processors to answer false
-	 for values in the interpreter or the object memory.    Restrict our use of offsets to reference
-	 addresses within the method zone, rather than checking for a 32-bit offset, si as to keep the
-	 simulator and real VM in sync."
-
-	^cogit addressIsInCodeZone: anAddress
+CogX64Compiler >> isWithinMwOffsetRange: anImmediate [
+	"Answer if an immediate value can be used as offset in a MoveMw:r:R: or similar instruction.
+	 The X64 backend only encodes 32bit signed immediates for now"
+
+	^ self is32BitSignedImmediate: anImmediate
 ]
 
 { #category : #accessing }

smalltalksrc/VMMaker/Integer.extension.st

@@ -67,8 +67,15 @@ Integer >> asSmallIntegerObj [
 
 { #category : #'*VMMaker-interpreter simulator' }
 Integer >> asUnsignedInteger [
-
-	^ self
+	"Since the simulator deals with positive integers most of the time we assert that the receiver is greater than zero.
+	 But one major exception is stack pointers in the StackInterpreterSimulator, which are negative.  So don't fail
+	 if the sender is a StackInterpreter and the receiver could be a stack pointer."
+	self >= 0 ifFalse:
+		[self assert: (((thisContext sender methodClass includesBehavior: CoInterpreter)
+					   and: [self between: Cogit maxNegativeErrorCode and: -1])
+					or: [(thisContext sender methodClass includesBehavior: StackInterpreter)
+					   and: [thisContext sender receiver stackPages couldBeFramePointer: self]])].
+	^self
 ]
 
 { #category : #'*VMMaker-interpreter simulator' }