PE-Assembler: De novo assembler using short paired-end reads
Assembler
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Transcript of Assembler
Assemblers
Design of 2-Pass AssemblersAgenda Introduction Advanced Assembler DirectivesORIGINEQULT ORGPass I of the AssemblerData Structure used in Pass IOPTAB SYMTABLITTABPOOLTABAlgorithmIntermediate codeDeclaration and Assembler Directive Processing Pass II of the AssemblerIntroductionSourceProgramAssemblerObjectCodeLoaderExecutable CodeLinkerConvert mnemonic operation codes to their machine language equivalentsConvert symbolic operands to their equivalent machine addresses Build the machine instructions in the proper formatConvert the data constants to internal machine representationsWrite the object program and the assembly listingIntroductionTwo Pass Assembler Read from input lineLABEL, OPCODE, OPERANDPass 1Pass 2 IntermediatefileObject codesSourceprogramOPTABSYMTABSYMTABIntroduction: Design of 2 - Pass AssemblerPass 1Separate the Symbol, Mnemonic opcode and operand fieldsBuild the symbol tablePerform LC Processing Construct Intermediate RepresentationPass 2Synthesize the target programAdvanced Assembler DirectivesORIGINEQU
Advanced Assembler DirectivesORIGINEQU
Syntax: ORIGIN < Address Specification>
Advanced Assembler DirectivesORIGINEQU
Syntax: EQU
E.g. MAXLENEQU4096Pass I of AssemblerPass I Uses following Data StructuresOPTABSYMTABLITTABPOOLTABPass I of AssemblerPass I Uses following Data StructuresOPTAB : A Table of Mnemonics & related infoSYMTABLITTABPOOLTAB
Pass I of AssemblerPass I Uses following Data StructuresOPTABSYMTAB: Symbol TableLITTABPOOLTAB
Pass I of AssemblerPass I Uses following Data StructuresOPTABSYMTABLITTAB: Table of Literals used in programPOOLTAB
Pass I of AssemblerPass I Uses following Data StructuresOPTABSYMTABLITTABPOOLTAB: A table of information concerning literal pool
Algorithm
Algorithm