Fujitsu Fujitsu SPARC64 V manual TSB Organization, TSB Pointer Formation

F.3.3 TSB Organization

IMPL. DEP. #227: The maximum number of entries in a TSB is implementation dependent in JPS1. See impl. dep. #228 for the limitation of TSB_size in TSB registers.

SPARC64 V supports a maximum of 16 million lines in the common TSB and a maximum 32 million lines in the split TSB. The maximum number N in FIGURE F-4 of Commonality is 16 million (16 * 220).

F.4.2 TSB Pointer Formation

IMPL. DEP. #228: Whether TSB_Hash is supplied from a TSB Extension Register or from a context-ID register is implementation dependent in JPS1. Only for cases of direct hash with context-ID can the width of the TSB_size field be wider than 3 bits.

On SPARC64 V, TSB_Hash is supplied from a context-ID register. The width of the TSB_size field is 4 bits.

IMPL. DEP. #229: Whether the implementation generates the TSB Base address by exclusive-ORing the TSB Base Register and a TSB Extension Register or by taking the TSB_Base field directly from the TSB Extension Register is implementation dependent in JPS1. This implementation dependency is only to maintain compatibility with the TLB miss handling software of UltraSPARC I/II.

On SPARC64 V, when ASI_MCNTL.JPS1_TSBP = 1, the TSB Base address is generated by taking TSB_Base field directly from the TSB Extension Register.

TSB Pointer Formation

On SPARC64 V, the number N in the following equations ranges from 0 to 15; N is defined to be the TSB_Size field of the TSB Base or TSB Extension Register.

SPARC64 V supports the TSB Base from TSB Extension Registers as follows when ASI_MCNTL.JPS1_TSBP = 1.

For a shared TSB (TSB Register split field = 0):

8K_POINTER = TSB_Extension[63:13+N] (VA[21+N:13] ⊕ TSB_Hash) 0000

64K_POINTER = TSB_Extension[63:13+N] (VA[24+N:16] ⊕ TSB_Hash) 0000

For a split TSB (TSB Register split field = 1):

88 SPARC JPS1 Implementation Supplement: Fujitsu SPARC64 V • Release 1.0, 1 July 2002