Le 09/07/12 21:32, Michael Walle a écrit : > > > Yann Sionneau <y...@minet.net> schrieb: > >> Le 09/07/12 18:28, Michael Walle a écrit : >>> >>> Yann Sionneau <y...@minet.net> schrieb: >>> >>>> Hey, >>>> >>>> Michael Walle asked me to publish a documentation of Milkymist MMU >> in >>>> order for him to study the feasibility of implementing a model for >> this >>>> MMU in QEmu. >>>> Documenting is always something one needs to do at some point, so >> here >>>> it is, written very quickly in a small text file. >>>> >>>> I hope it is clear enough, if you have any question: do not hesitate >> to >>>> ask me :) >>>> This is not a complete documentation, it does not say anything yet >>>> about >>>> generated exceptions/TLB miss/page fault etc. >>> thanks. still missing: >>> - csr numbers >>> - how to enable and disable the mmu >> I updated the wiki documentation with the following information: >> >> CSR ids (used in LM32 opcodes): >> >> * TLBCTRL: 0x1C >> * TLBVADDR (and DTLBMA): 0x1D >> * TLBPADDR (and ITLBMA): 0x1E >> >> >> Enabling the ITLB: >> >> mvi r1, 0x8 >> wcsr TLBCTRL, r1 >> >> Enabling the DTLB: >> >> mvi r1, 0x9 >> wcsr TLBCTRL, r1 >> > > and how do disable it again? >
I copy paste my IRC speech without all my mistakes *sorry tired* : switching OFF T/D TLB is using the command "switch to kernel mode" : number 5'h4 (0x4 for non-native verilog speakers) so you shift left the command ID (because lowest bit will be used to chose whether you speak to ITLB or DTLB) => 0x8 so you write 0x8 to TLBCTRL to switch OFF ITLB, and 0x9 (lowest bit set) to switch OFF DTLB. -- Yann Sionneau _______________________________________________ http://lists.milkymist.org/listinfo.cgi/devel-milkymist.org IRC: #milkymist@Freenode
