Burst Buffer Controller 2 Module
MPC561/MPC563 Reference Manual, Rev. 1.2
Freescale Semiconductor
4-15
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BTE Miss — The target address and instruction code data will be stored in one of the BTE entries
defined by its control logic. Up to four instructions and their corresponding addresses subsequent
to the COF target instruction may be saved in each BTE entry. The number of valid instructions
currently stored in the BTE entry is written into the VDC field of the current BTE entry. The valid
flag is set at the end of this process. The entry to be replaced upon miss is chosen based on FIFO
replacement method. Thus the BTB can support up to eight different branch target addresses in a
program loop.
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BTE Hit — When the target address of a branch matches one of the valid BTE entries, two
activities take place in parallel:
— The BTB supplies all the valid instructions in the matched entry to the RCPU.
— The BIU starts to prefetch new instructions (and ICDU decompresses them in compressed
mode) from the address following the last instruction that is stored in the matched BTB entry.
The BBC will supply these new instructions to the RCPU after all the stored instructions in the
matched BTB entry were delivered.
In case of a BTB hit, the impact of instruction decompression latency (in compressed mode) is eliminated
as well as a latency of instruction storage memory device.
Summary of Contents for MPC561
Page 84: ...MPC561 MPC563 Reference Manual Rev 1 2 lxxxiv Freescale Semiconductor...
Page 144: ...Signal Descriptions MPC561 MPC563 Reference Manual Rev 1 2 2 46 Freescale Semiconductor...
Page 206: ...Central Processing Unit MPC561 MPC563 Reference Manual Rev 1 2 3 62 Freescale Semiconductor...
Page 302: ...Reset MPC561 MPC563 Reference Manual Rev 1 2 7 14 Freescale Semiconductor...
Page 854: ...Time Processor Unit 3 MPC561 MPC563 Reference Manual Rev 1 2 19 24 Freescale Semiconductor...
Page 968: ...Development Support MPC561 MPC563 Reference Manual Rev 1 2 23 54 Freescale Semiconductor...
Page 1144: ...Internal Memory Map MPC561 MPC563 Reference Manual Rev 1 2 B 34 Freescale Semiconductor...
Page 1212: ...TPU3 ROM Functions MPC561 MPC563 Reference Manual Rev 1 2 D 60 Freescale Semiconductor...
Page 1216: ...Memory Access Timing MPC561 MPC563 Reference Manual Rev 1 2 E 4 Freescale Semiconductor...