page_title: Clipper architecture
section_title: Versions
hierarchical_section_title: Clipper architecture / Versions
caption_attribution_description: English: Die shot of Intergraph Clipper C300 microprocessor (CPU) marked CYIM01500.
context_page_description: The Clipper architecture is a 32-bit RISC-like instruction set architecture designed by Fairchild Semiconductor. The architecture never enjoyed much market success, and the only computer manufacturers to create major product lines using Clipper processors were Intergraph and High Level Hardware. The first processors using the Clipper architecture were designed and sold by Fairchild, but the division responsible for them was subsequently sold to Intergraph in 1987; Intergraph continued work on Clipper processors for use in its own systems.
  The Clipper architecture used a simplified instruction set compared to earlier CISC architectures, but it did incorporate some more complicated instructions than were present in other contemporary RISC processors. These instructions were implemented in a so-called Macro Instruction ROM within the Clipper CPU. This scheme allowed the Clipper to have somewhat higher code density than other RISC CPUs.
context_section_description: The initial Clipper microprocessor produced by Fairchild was the C100, which became available in 1986.  This was followed by the faster C300 from Intergraph in 1988.  The final model of the Clipper was the C400, released in 1990, which was extensively redesigned to be faster and added more floating-point registers. The C400 processor combined two key architectural techniques to achieve a new level of performance — superscalar instruction dispatch and superpipelined operation.
  While many processors of the time used either superscalar instruction dispatch or superpipelined operation, the Clipper C400 was the first processor to use both.
  Intergraph started work on a subsequent Clipper processor design known as the C5, but this was never completed or released.  Nonetheless, some advanced processor design techniques were devised for the C5, and Intergraph was granted patents on these.  These patents, along with the original Clipper patents, have been the basis of patent-infringement lawsuits by Intergraph against Intel and other companies.
  Unlike many other microprocessors, the Clipper processors were actually sets of several distinct chips.  The C100 and C300 consist of three chips: one central processing unit containing both an integer unit and a floating point unit, and two cache and memory management units (CAMMUs), one responsible for data and one for instructions.  The CAMMUs contained caches, translation lookaside buffers, and support for memory protection and virtual memory.  The C400 consists of four basic units: an integer CPU, an FPU, an MMU, and a cache unit.  The initial version used one chip each for the CPU and FPU and discrete elements for the MMU and cache unit, but in later versions the MMU and cache unit were combined into one CAMMU chip.
caption: Die of Clipper C300 CPU
exif: {"Image Make": "Canon", "Image Model": "Canon PowerShot A4000 IS", "Image Orientation": "Horizontal (normal)", "Image XResolution": "180", "Image YResolution": "180", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "GIMP 2.8.4", "Image DateTime": "2016:01:09 01:52:49", "Image YCbCrPositioning": "Co-sited", "Image ExifOffset": "214", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "1152", "Thumbnail JPEGInterchangeFormatLength": "12185", "EXIF ExposureTime": "1/1250", "EXIF FNumber": "16/5", "EXIF ISOSpeedRatings": "100", "EXIF ExifVersion": "0230", "EXIF DateTimeOriginal": "2015:11:10 21:58:28", "EXIF DateTimeDigitized": "2015:11:10 21:58:28", "EXIF ComponentsConfiguration": "YCbCr", "EXIF CompressedBitsPerPixel": "3", "EXIF ShutterSpeedValue": "329/32", "EXIF ApertureValue": "107/32", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "107/32", "EXIF SubjectDistance": "21/50", "EXIF MeteringMode": "Pattern", "EXIF Flash": "Flash did not fire, compulsory flash mode", "EXIF FocalLength": "8117/1000", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "3352", "EXIF ExifImageLength": "3222", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "Interoperability RelatedImageWidth": "4608", "Interoperability RelatedImageLength": "3456", "EXIF InteroperabilityOffset": "1004", "EXIF FocalPlaneXResolution": "2304000/121", "EXIF FocalPlaneYResolution": "1728000/91", "EXIF FocalPlaneResolutionUnit": "2", "EXIF SensingMethod": "One-chip color area", "EXIF FileSource": "Digital Camera", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Manual", "EXIF DigitalZoomRatio": "1", "EXIF SceneCaptureType": "Standard"}