Difference between revisions of "FP11-C Floating-Point Processor"
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| − | The '''FP11-C''' was a [[Floating point processor|FPP]] used in the [[PDP-11/45]] and [[PDP-11/70]] computers (KB11-D and KB11-C CPU variants, respectively) | + | The '''FP11-C''' was a [[Floating point processor|FPP]] used in the [[PDP-11/45]] and [[PDP-11/70]] computers (KB11-D and KB11-C CPU variants thereof, respectively); it operated in parallel with the main processor, so that two instructions (one floating point, one regular) could be processed at the same time. |
| − | The FP11-C included the following boards: | + | Like the [[FP11-B]], it supported short (32 bit) and long (64 bit) floating point numbers; both forms used an 8 bit exponent (in 'excess 0200' notation, giving an exponent range of +127. to -128.), a sign bit, and the remaining bits were the fractional part. A state bit controlled whether the FP11-C operated in short or long mode. |
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| + | The FP11-C contained 6 internal registers, each capable of holding either a short or long floating point value. | ||
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| + | ==Implementation== | ||
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| + | The FP11-C used a clock which is synchronized to the basic CPU's clock. It plugged into special pre-wired slots in the CPU's [[backplane]], and included the following boards: | ||
* M8128 ROM and ROM Control | * M8128 ROM and ROM Control | ||
Revision as of 03:05, 25 April 2016
The FP11-C was a FPP used in the PDP-11/45 and PDP-11/70 computers (KB11-D and KB11-C CPU variants thereof, respectively); it operated in parallel with the main processor, so that two instructions (one floating point, one regular) could be processed at the same time.
Like the FP11-B, it supported short (32 bit) and long (64 bit) floating point numbers; both forms used an 8 bit exponent (in 'excess 0200' notation, giving an exponent range of +127. to -128.), a sign bit, and the remaining bits were the fractional part. A state bit controlled whether the FP11-C operated in short or long mode.
The FP11-C contained 6 internal registers, each capable of holding either a short or long floating point value.
Implementation
The FP11-C used a clock which is synchronized to the basic CPU's clock. It plugged into special pre-wired slots in the CPU's backplane, and included the following boards:
- M8128 ROM and ROM Control
- M8129 Exponent and Data Path
- M8126 Fraction Data Path - High Order
- M8127 Fraction Data Path - Low Order
