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Moved WFI timeout into privdec

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This commit is contained in:
David Harris 2022-05-12 16:22:39 +00:00
parent 21c1e58829
commit 1d01bc98a4
2 changed files with 20 additions and 36 deletions
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19
pipelined/src/privileged/privdec.sv
View File

@ -32,18 +32,21 @@
`include "wally-config.vh"
module privdec (
input logic clk, reset,
input logic [31:20] InstrM,
input logic PrivilegedM, IllegalIEUInstrFaultM, IllegalCSRAccessM, IllegalFPUInstrM,
input logic WFITimeoutM,
input logic [1:0] PrivilegeModeW,
input logic STATUS_TSR, STATUS_TVM,
input logic STATUS_TSR, STATUS_TVM, STATUS_TW,
input logic [1:0] STATUS_FS,
output logic IllegalInstrFaultM,
output logic sretM, mretM, ecallM, ebreakM, wfiM, sfencevmaM);
logic IllegalPrivilegedInstrM, IllegalOrDisabledFPUInstrM;
logic WFITimeoutM;
///////////////////////////////////////////
// Decode privileged instructions
///////////////////////////////////////////
assign sretM = PrivilegedM & (InstrM[31:20] == 12'b000100000010) & `S_SUPPORTED &
(PrivilegeModeW == `M_MODE || PrivilegeModeW == `S_MODE & ~STATUS_TSR);
assign mretM = PrivilegedM & (InstrM[31:20] == 12'b001100000010) & (PrivilegeModeW == `M_MODE);
@ -53,7 +56,19 @@ module privdec (
assign sfencevmaM = PrivilegedM & (InstrM[31:25] == 7'b0001001) &
(PrivilegeModeW == `M_MODE | (PrivilegeModeW == `S_MODE & ~STATUS_TVM));
///////////////////////////////////////////
// WFI timeout Privileged Spec 3.1.6.5
///////////////////////////////////////////
if (`U_SUPPORTED) begin:wfi
logic [`WFI_TIMEOUT_BIT:0] WFICount, WFICountPlus1;
assign WFICountPlus1 = WFICount + 1;
floprc #(`WFI_TIMEOUT_BIT+1) wficountreg(clk, reset, ~wfiM, WFICountPlus1, WFICount); // count while in WFI
assign WFITimeoutM = ((STATUS_TW & PrivilegeModeW != `M_MODE) | (`S_SUPPORTED & PrivilegeModeW == `U_MODE)) & WFICount[`WFI_TIMEOUT_BIT];
end else assign WFITimeoutM = 0;
///////////////////////////////////////////
// Fault on illegal instructions
///////////////////////////////////////////
assign IllegalPrivilegedInstrM = PrivilegedM & ~(sretM|mretM|ecallM|ebreakM|wfiM|sfencevmaM);
assign IllegalOrDisabledFPUInstrM = IllegalFPUInstrM | (STATUS_FS == 2'b00);
assign IllegalInstrFaultM = (IllegalIEUInstrFaultM & IllegalOrDisabledFPUInstrM) | IllegalPrivilegedInstrM | IllegalCSRAccessM |

37
pipelined/src/privileged/privileged.sv
View File

@ -111,45 +111,14 @@ module privileged (
privmode privmode(.clk, .reset, .StallW, .TrapM, .mretM, .sretM, .CauseM,
.MEDELEG_REGW, .MIDELEG_REGW, .STATUS_MPP, .STATUS_SPP, .NextPrivilegeModeM, .PrivilegeModeW);
/*
// get bits of DELEG registers based on CAUSE
assign md = CauseM[`XLEN-1] ? MIDELEG_REGW[CauseM[3:0]] : MEDELEG_REGW[CauseM[`LOG_XLEN-1:0]];
// PrivilegeMode FSM
always_comb begin
if (TrapM) begin // Change privilege based on DELEG registers (see 3.1.8)
if (`S_SUPPORTED & md & (PrivilegeModeW == `U_MODE | PrivilegeModeW == `S_MODE))
NextPrivilegeModeM = `S_MODE;
else NextPrivilegeModeM = `M_MODE;
end else if (mretM) NextPrivilegeModeM = STATUS_MPP;
else if (sretM) begin
if (STATUS_TSR & PrivilegeModeW == `S_MODE) begin
NextPrivilegeModeM = PrivilegeModeW;
end else NextPrivilegeModeM = {1'b0, STATUS_SPP};
end else NextPrivilegeModeM = PrivilegeModeW;
end
flopenl #(2) privmodereg(clk, reset, ~StallW, NextPrivilegeModeM, `M_MODE, PrivilegeModeW);
*/
///////////////////////////////////////////
// WFI timeout Privileged Spec 3.1.6.5
///////////////////////////////////////////
if (`U_SUPPORTED) begin:wfi
logic [`WFI_TIMEOUT_BIT:0] WFICount, WFICountPlus1;
assign WFICountPlus1 = WFICount + 1;
floprc #(`WFI_TIMEOUT_BIT+1) wficountreg(clk, reset, ~wfiM, WFICountPlus1, WFICount); // count while in WFI
assign WFITimeoutM = ((STATUS_TW & PrivilegeModeW != `M_MODE) | (`S_SUPPORTED & PrivilegeModeW == `U_MODE)) & WFICount[`WFI_TIMEOUT_BIT];
end else assign WFITimeoutM = 0;
///////////////////////////////////////////
// decode privileged instructions
///////////////////////////////////////////
privdec pmd(.InstrM(InstrM[31:20]),
.PrivilegedM, .IllegalIEUInstrFaultM, .IllegalCSRAccessM, .IllegalFPUInstrM, .WFITimeoutM,
.PrivilegeModeW, .STATUS_TSR, .STATUS_TVM, .STATUS_FS, .IllegalInstrFaultM,
privdec pmd(.clk, .reset, .InstrM(InstrM[31:20]),
.PrivilegedM, .IllegalIEUInstrFaultM, .IllegalCSRAccessM, .IllegalFPUInstrM,
.PrivilegeModeW, .STATUS_TSR, .STATUS_TVM, .STATUS_TW, .STATUS_FS, .IllegalInstrFaultM,
.sretM, .mretM, .ecallM, .ebreakM, .wfiM, .sfencevmaM);
///////////////////////////////////////////