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Further TranslationVAdr simplification

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This commit is contained in:
David Harris 2021-07-17 19:24:37 -04:00
parent b785a20f90
commit 2b1fdfbae2
1 changed files with 21 additions and 18 deletions
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39
wally-pipelined/src/mmu/pagetablewalker.sv
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@ -121,27 +121,30 @@ module pagetablewalker
// TranslationPAdr mux
if (`XLEN==32) begin // RV32
logic [9:0] VPN1, VPN0, VPN;
logic [9:0] VPN;
logic [`PPN_BITS-1:0] PPN;
assign VPN1 = TranslationVAdr[31:22];
assign VPN0 = TranslationVAdr[21:12];
assign VPN = ((WalkerState == LEVEL1_SET_ADR) | (WalkerState == LEVEL1_READ)) ? VPN1 : VPN0;
assign VPN = ((WalkerState == LEVEL1_SET_ADR) | (WalkerState == LEVEL1_READ)) ? TranslationVAdr[31:22] : TranslationVAdr[21:12]; // select VPN field based on HPTW state
assign PPN = ((WalkerState == LEVEL1_SET_ADR) | (WalkerState == LEVEL1_READ)) ? BasePageTablePPN : CurrentPPN;
assign TranslationPAdr = {PPN, VPN, 2'b00};
/* always_comb
case (WalkerState)
LEVEL1_SET_ADR: TranslationPAdr = {BasePageTablePPN, VPN1, 2'b00};
LEVEL1_READ: TranslationPAdr = {BasePageTablePPN, VPN1, 2'b00};
LEVEL1: if (NextWalkerState == LEAF) TranslationPAdr = 0; // {2'b00, TranslationVAdr[31:0]}; // *** 7/17/21 Ross will check this and similar in LEVEL0 and LEAF
else TranslationPAdr = {CurrentPPN, VPN0, 2'b00};
LEVEL0_SET_ADR: TranslationPAdr = {CurrentPPN, VPN0, 2'b00};
LEVEL0_READ: TranslationPAdr = {CurrentPPN, VPN0, 2'b00};
LEVEL0: TranslationPAdr = 0; // {2'b00, TranslationVAdr[31:0]};
LEAF: TranslationPAdr = 0; // {2'b00, TranslationVAdr[31:0]};
default: TranslationPAdr = 0; // cause seg fault if this is improperly used
endcase */
end else begin // RV64
logic [8:0] VPN3, VPN2, VPN1, VPN0;
logic [8:0] VPN;
logic [`PPN_BITS-1:0] PPN;
always_comb
case (WalkerState)
LEVEL3_SET_ADR: VPN = TranslationVAdr[47:39];
LEVEL3_READ: VPN = TranslationVAdr[47:39];
LEVEL3: VPN = TranslationVAdr[38:30];
LEVEL2_SET_ADR: VPN = TranslationVAdr[38:30];
LEVEL2_READ: VPN = TranslationVAdr[38:30];
LEVEL2: VPN = TranslationVAdr[29:21];
LEVEL1_SET_ADR: VPN = TranslationVAdr[29:21];
LEVEL1_READ: VPN = TranslationVAdr[29:21];
default: VPN = TranslationVAdr[20:12];
endcase
assign PPN = ((WalkerState == LEVEL3_SET_ADR) | (WalkerState == LEVEL3_READ) |
(SvMode != `SV48 & ((WalkerState == LEVEL2_SET_ADR) | (WalkerState == LEVEL2_READ)))) ? BasePageTablePPN : CurrentPPN;
assign TranslationPAdr = {PPN, VPN, 3'b000};
/*
assign VPN3 = TranslationVAdr[47:39];
assign VPN2 = TranslationVAdr[38:30];
assign VPN1 = TranslationVAdr[29:21];
@ -165,7 +168,7 @@ module pagetablewalker
LEVEL0: TranslationPAdr = 0; //TranslationVAdr[`PA_BITS-1:0];
LEAF: TranslationPAdr = 0; //TranslationVAdr[`PA_BITS-1:0];
default: TranslationPAdr = 0; // cause seg fault if this is improperly used
endcase
endcase */
end
if (`XLEN == 32) begin