[prim_cipher_pkg] Reuse sbox4_8bit to build wider sbox layers
Signed-off-by: Michael Schaffner <msf@opentitan.org>
diff --git a/hw/ip/prim/rtl/prim_cipher_pkg.sv b/hw/ip/prim/rtl/prim_cipher_pkg.sv
index 81e0020..f3bf027 100644
--- a/hw/ip/prim/rtl/prim_cipher_pkg.sv
+++ b/hw/ip/prim/rtl/prim_cipher_pkg.sv
@@ -340,8 +340,8 @@
function automatic logic [15:0] sbox4_16bit(logic [15:0] state_in, logic [15:0][3:0] sbox4);
logic [15:0] state_out;
// note that if simulation performance becomes an issue, this loop can be unrolled
- for (int k = 0; k < 16/4; k++) begin
- state_out[k*4 +: 4] = sbox4[state_in[k*4 +: 4]];
+ for (int k = 0; k < 2; k++) begin
+ state_out[k*8 +: 8] = sbox4_8bit(state_in[k*8 +: 8], sbox4);
end
return state_out;
endfunction : sbox4_16bit
@@ -349,8 +349,8 @@
function automatic logic [31:0] sbox4_32bit(logic [31:0] state_in, logic [15:0][3:0] sbox4);
logic [31:0] state_out;
// note that if simulation performance becomes an issue, this loop can be unrolled
- for (int k = 0; k < 32/4; k++) begin
- state_out[k*4 +: 4] = sbox4[state_in[k*4 +: 4]];
+ for (int k = 0; k < 4; k++) begin
+ state_out[k*8 +: 8] = sbox4_8bit(state_in[k*8 +: 8], sbox4);
end
return state_out;
endfunction : sbox4_32bit
@@ -358,8 +358,8 @@
function automatic logic [63:0] sbox4_64bit(logic [63:0] state_in, logic [15:0][3:0] sbox4);
logic [63:0] state_out;
// note that if simulation performance becomes an issue, this loop can be unrolled
- for (int k = 0; k < 64/4; k++) begin
- state_out[k*4 +: 4] = sbox4[state_in[k*4 +: 4]];
+ for (int k = 0; k < 8; k++) begin
+ state_out[k*8 +: 8] = sbox4_8bit(state_in[k*8 +: 8], sbox4);
end
return state_out;
endfunction : sbox4_64bit
