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Motorola FPU
  Motorola 6888x FPU XC68881RC12
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  Motorola 6888x FPU MC68881RC16B
  Motorola 6888x FPU MC68881RC20D
  Motorola 6888x FPU MC68881RC25B
  Motorola 6888x FPU MC68882FN20A
  Motorola 6888x FPU MC68882RC33A
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The Motorola 68881/68882 FPUs
The 68020 and 68030 CPUs were designed with the separate 68881 chip in mind. Their instruction sets reserved the "F-line" instructions - that is, all opcodes beginning with the hexadecimal digit "F" were "traps" which would throw an interrupt, handing control to the computer's operating system. If a 68881 were present in the system, the CPU would allow it to execute the instruction. If not, the OS would either call an FPU emulator to execute the instruction using 68020 integer-based software code, or would return an error code to the program.
 
The CPU/FPU pair were designed such that both could run at the same time. When the CPU encountered a 68881 instruction, it would hand the FPU all operands needed for that instruction, and then the FPU would release the CPU to go on and execute the next instruction.
 
When the Motorola 68040 processor was introduced, it included the FPU internally. Most instructions and numeric representation modes from the 68881 were supported in hardware, but some were not, and were emulated through a software package.
Motorola 6888x FPU XC68881RC12
Motorola 6888x FPU XC68881RC12 Top Side
XC68881RC12
3A79J8552
Motorola 6888x FPU XC68881RC12 Back Side
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Core Frequency:12 MHz
Board Frequency:12 MHz
Transistors:155,000
Manufactured:week 52/1985
Package Type:Ceramic
PGA-68
Goldcap
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Motorola 6888x FPU MC68881RC16A
Motorola 6888x FPU MC68881RC16A Top Side
MC68881RC16A
2A93N8637
Motorola 6888x FPU MC68881RC16A Back Side
Donated by Christian Lederer. Thanks a lot!  
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Core Frequency:16 MHz
Board Frequency:16 MHz
Transistors:155,000
Manufactured:week 37/1986
Package Type:Ceramic
PGA-68
Goldcap
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Motorola 6888x FPU MC68881RC16B
Motorola 6888x FPU MC68881RC16B Top Side
MC68881RC16B
2B81G8823
MALAYSIA
YWYWQ
Motorola 6888x FPU MC68881RC16B Back Side
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Core Frequency:16 MHz
Board Frequency:16 MHz
Transistors:155,000
Manufactured:week 23/1988
Package Type:Ceramic
PGA-68
Goldcap
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Motorola 6888x FPU MC68881RC20D
Motorola 6888x FPU MC68881RC20D Top Side
MC68881RC20D
2B81G
QEGD8905
MALAYSIA
AEGDQ-12
Motorola 6888x FPU MC68881RC20D Back Side
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Core Frequency:20 MHz
Board Frequency:20 MHz
Transistors:155,000
Manufactured:week 05/1989
Made in:Malaysia
Package Type:Ceramic
PGA-68
Goldcap
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Motorola 6888x FPU MC68881RC25B
Motorola 6888x FPU MC68881RC25B Top Side
MC68881RC25B
2B81G8831
MALAYSIA
YWYWQ
Motorola 6888x FPU MC68881RC25B Back Side
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Core Frequency:25 MHz
Board Frequency:25 MHz
Transistors:155,000
Manufactured:week 31/1988
Package Type:Ceramic
PGA-68
Goldcap
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The Motorola 68882 was an improved version of the 68881, with better pipelining, and eventually available at higher clock speeds. Its instruction set was exactly the same as that of the 68881. Motorola claimed in some marketing literature that it executed some instructions 40% faster than a 68881 at the same clock speed, though this did not reflect typical performance at all.
Motorola 6888x FPU MC68882FN20A
Motorola 6888x FPU MC68882FN20A Top Side
MC68882FN20A
1C12R
QESL9213
Motorola 6888x FPU MC68882FN20A Back Side
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Core Frequency:20 MHz
Board Frequency:20 MHz
Transistors:176,000
Manufactured:week 13/1992
Package Type:Plastik
PLCC-64
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Motorola 6888x FPU MC68882RC33A
Motorola 6888x FPU MC68882RC33A Top Side
MC68882RC33A
OC35H
QEFR8947
MALAYSIA
BTFRQ-2
Motorola 6888x FPU MC68882RC33A Back Side
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Core Frequency:33 MHz
Board Frequency:33 MHz
Transistors:176,000
Manufactured:week 47/1989
Made in:Malaysia
Package Type:Ceramic
PGA-68
Goldcap
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