Move byte reversal of stores to first cycle

We are seeing some timing issues with the second cycle of loadstore,
and  we aren't doing much in the first cycle, so move it here.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
jtag-port
Anton Blanchard 5 years ago committed by Anton Blanchard
parent a4c8dd860a
commit a061924a78

@ -4,6 +4,7 @@ use ieee.numeric_std.all;

library work;
use work.common.all;
use work.helpers.all;

-- 2 cycle LSU
-- We calculate the address in the first cycle
@ -47,6 +48,11 @@ begin
v.update := l_in.update;
v.update_reg := l_in.update_reg;

-- byte reverse stores in the first cycle
if v.load = '0' and l_in.byte_reverse = '1' then
v.data := byte_reverse(l_in.data, to_integer(unsigned(l_in.length)));
end if;

v.addr := lsu_sum;

-- Update registers

@ -102,10 +102,6 @@ begin
m_tmp.we <= '1';

data := l_in.data;
if l_in.byte_reverse = '1' then
data := byte_reverse(data, to_integer(unsigned(l_in.length)));
end if;

m_tmp.dat <= std_logic_vector(shift_left(unsigned(data), wishbone_data_shift(l_in.addr)));

assert l_in.sign_extend = '0' report "sign extension doesn't make sense for stores" severity failure;

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