https://openjdk.java.net/ 
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package jdk.vm.ci.meta;


Provides memory access operations for the target VM.

/**
 * Provides memory access operations for the target VM.
 */
public interface MemoryAccessProvider {

    
Reads a primitive value using a base address and a displacement.

Params:
  • kind – the JavaKind of the returned JavaConstant object
  • base – the base address from which the value is read
  • displacement – the displacement within the object in bytes
  • bits – the number of bits to read from memory
Throws:
Returns:the read value encapsulated in a JavaConstant object of JavaKind kind
/**
     * Reads a primitive value using a base address and a displacement.
     *
     * @param kind the {@link JavaKind} of the returned {@link JavaConstant} object
     * @param base the base address from which the value is read
     * @param displacement the displacement within the object in bytes
     * @param bits the number of bits to read from memory
     * @return the read value encapsulated in a {@link JavaConstant} object of {@link JavaKind} kind
     * @throws IllegalArgumentException if the read is out of bounds of the object or {@code kind}
     *             is {@link JavaKind#Void} or not {@linkplain JavaKind#isPrimitive() primitive}
     *             kind or {@code bits} is not 8, 16, 32 or 64
     */
    JavaConstant readPrimitiveConstant(JavaKind kind, Constant base, long displacement, int bits) throws IllegalArgumentException;

    
Reads a Java Object value using a base address and a displacement. 
Params:
  • base – the base address from which the value is read
  • displacement – the displacement within the object in bytes
Throws:
  • IllegalArgumentException – if the address computed from base and displacement does not denote a location holding an Object value
Returns:the read value encapsulated in a Constant object
/**
     * Reads a Java {@link Object} value using a base address and a displacement.
     *
     * @param base the base address from which the value is read
     * @param displacement the displacement within the object in bytes
     * @return the read value encapsulated in a {@link Constant} object
     * @throws IllegalArgumentException if the address computed from {@code base} and
     *             {@code displacement} does not denote a location holding an {@code Object} value
     */
    JavaConstant readObjectConstant(Constant base, long displacement);
}