[kmac] Reverse the PREFIX order
Changed the !!PREFIX register order in little-endian way.
Signed-off-by: Eunchan Kim <eunchan@opentitan.org>
diff --git a/hw/ip/kmac/data/kmac.hjson b/hw/ip/kmac/data/kmac.hjson
index 866a7c9..e92a659 100644
--- a/hw/ip/kmac/data/kmac.hjson
+++ b/hw/ip/kmac/data/kmac.hjson
@@ -484,7 +484,7 @@
800-185 specification.
Order of Prefix is:
- prefix[end:0] := {PREFIX0, PREFIX1, ... }
+ prefix[end:0] := {PREFIX(N-1), ..., PREFIX(1), PREFIX(0) }
The registers are allowed to be updated when the engine is in Idle state.
If the engine computes the hash, it discards any attempts to update the secret keys
diff --git a/hw/ip/kmac/rtl/kmac.sv b/hw/ip/kmac/rtl/kmac.sv
index ed3d045..b6baa96 100644
--- a/hw/ip/kmac/rtl/kmac.sv
+++ b/hw/ip/kmac/rtl/kmac.sv
@@ -195,7 +195,7 @@
// Function-name N and Customization input string S
always_comb begin
for (int i = 0 ; i < NumWordsPrefix; i++) begin
- ns_prefix[32*i+:32] = reg2hw.prefix[NumWordsPrefix-1 - i].q;
+ ns_prefix[32*i+:32] = reg2hw.prefix[i].q;
end
end
