bitsort: Fix bperm instruction (#456)

The result byte needs to be zero when the index byte value is >= 64. Fixes: 23ff954059 ("core: Change bperm to a simpler and slower implementation", 2025-01-07) Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
1 day ago · 0b3df8ab00
parent da695e7927
commit 0b3df8ab00
1 changed files with 3 additions and 1 deletions
--- a/bitsort.vhdl
+++ b/bitsort.vhdl
@ -108,7 +108,9 @@ begin
    end process;

    -- bit permutation
-    bperm_res(7) <= rb_bp(to_integer(unsigned(not rs_sr(5 downto 0)))) when not is_X(rs_sr)
+    bperm_res(7) <= (rb_bp(to_integer(unsigned(not rs_sr(5 downto 0))))
+                     and not (rs_sr(6) or rs_sr(7)))
+                    when not is_X(rs_sr)
                    else 'X';

    bperm_r: process(clk)