1 Pertemuan 16 Instruction Set 2 Matakuliah: H0344/Organisasi dan Arsitektur Komputer Tahun: 2005 Versi: 1/1

2 Learning Outcomes Pada akhir pertemuan ini, diharapkan mahasiswa akan mampu : Menghubungkan instructions set untuk merealisasikan suatu proses sederhana

3 Outline Materi Machine Instruction Characteristics Types of Operands Types of Operation Assembly Language Addressing Instruction Formats

4 Addressing Addressing Modes

5 Addressing Basic Addressing Modes ModesAlgorithmPrincipal AdvantagePrincipal Disadvantage ImmediateOperand = ANo memory referenceLimited operand magnitude DirectEA = ASimpleLimited address space IndirectEA = (A)Large address spaceMultiple memory reference RegisterEA = RNo memory spaceLimited address space Register indirectEA = (R)Large address spaceExtra memory reference DisplacementEA = A + (R)FlexibilityComplexity DisplacementEA = top of stackNo memory referenceLimited application

6 Addressing Displacement Addressing Relative address Base register address Indexing Stack addressing Pushdown list Last in last out

7 Instruction formats Instruction length is affected by memory size, memory organization, bus structure, CPU complexity, and CPU speed. Instruction length determines the richness and flexibility of machine as seen by the assembly language programmer. There is clearly a trade off between the number of opcodes and the power of the addressing capability. The following interrelated factors go into determining the use of the addressing bits: Number of addressing modes Number of operand Register versus memory Number of register sets Address range Address granularity

8 Instruction formats Among the design principles that were employed in designing the instruction set were Orthogonality Completeness Direct addressing The principal price to pay for variable length instructions is an increase in the complexity of the CPU. Variable length instructions