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[pmp] constrain ADDR read-back for available modes

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stnolting 2024-02-16 06:45:30 +01:00
parent 769799f1be
commit b66d510dcd
1 changed files with 8 additions and 4 deletions
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12
rtl/core/neorv32_cpu_pmp.vhd
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@ -224,14 +224,18 @@ begin
begin
addr_rd(i) <= (others => '0');
addr_rd(i)(XLEN-1 downto pmp_lsb_c-2) <= csr.addr(i)(XLEN-1 downto pmp_lsb_c-2);
if (granularity_c = 8) then -- bit G-1 reads as zero in TOR or OFF mode
if (granularity_c = 8) and TOR_EN then -- bit G-1 reads as zero in TOR or OFF mode
if (csr.cfg(i)(cfg_ah_c) = '0') then -- TOR/OFF mode
addr_rd(i)(pmp_lsb_c) <= '0';
end if;
elsif (granularity_c > 8) then
addr_rd(i)(pmp_lsb_c-2 downto 0) <= (others => '1'); -- in NAPOT mode bits G-2:0 must read as one
if (csr.cfg(i)(cfg_ah_c) = '0') then -- TOR/OFF mode
addr_rd(i)(pmp_lsb_c-1 downto 0) <= (others => '0'); -- in TOR or OFF mode bits G-1:0 must read as zero
if NAP_EN then
addr_rd(i)(pmp_lsb_c-2 downto 0) <= (others => '1'); -- in NAPOT mode bits G-2:0 must read as one
end if;
if TOR_EN then
if (csr.cfg(i)(cfg_ah_c) = '0') then -- TOR/OFF mode
addr_rd(i)(pmp_lsb_c-1 downto 0) <= (others => '0'); -- in TOR or OFF mode bits G-1:0 must read as zero
end if;
end if;
end if;
end process address_read_back;