[topgen] Fix hex chunking code
The previous version didn't work correctly if a block happened to
start with a leading zero. The rewrite works with integers internally
instead of hex strings, which makes things rather simpler (and fixes
the bug).
Signed-off-by: Rupert Swarbrick <rswarbrick@lowrisc.org>
diff --git a/hw/top_earlgrey/rtl/autogen/top_earlgrey_rnd_cnst_pkg.sv b/hw/top_earlgrey/rtl/autogen/top_earlgrey_rnd_cnst_pkg.sv
index 01fb60b..57e9a87 100644
--- a/hw/top_earlgrey/rtl/autogen/top_earlgrey_rnd_cnst_pkg.sv
+++ b/hw/top_earlgrey/rtl/autogen/top_earlgrey_rnd_cnst_pkg.sv
@@ -61,7 +61,7 @@
////////////////////////////////////////////
// Compile-time random reset value for SRAM scrambling key.
parameter otp_ctrl_pkg::sram_key_t RndCnstSramCtrlRetAonSramKey = {
- 128'h738F30D9006289A1D7D9D0CE1DD7D7C
+ 128'h0738F30D9006289A1D7D9D0CE1DD7D7C
};
// Compile-time random reset value for SRAM scrambling nonce.
@@ -89,7 +89,7 @@
// Compile-time random bits for initial LFSR seed
parameter flash_ctrl_pkg::lfsr_seed_t RndCnstFlashCtrlLfsrSeed = {
- 32'h96F534D
+ 32'h096F534D
};
// Compile-time random permutation for LFSR output
@@ -183,7 +183,7 @@
// Compile-time random bits for generation seed when hmac destination selected
parameter keymgr_pkg::seed_t RndCnstKeymgrHmacSeed = {
- 256'hBC5F1A8862845852761603352213B7A034816103A781D0A4F5A0A911C1BCAFE
+ 256'h0BC5F1A8862845852761603352213B7A034816103A781D0A4F5A0A911C1BCAFE
};
// Compile-time random bits for generation seed when kmac destination selected
diff --git a/util/topgen/templates/toplevel_rnd_cnst_pkg.sv.tpl b/util/topgen/templates/toplevel_rnd_cnst_pkg.sv.tpl
index 9700c3d..b05f7bf 100644
--- a/util/topgen/templates/toplevel_rnd_cnst_pkg.sv.tpl
+++ b/util/topgen/templates/toplevel_rnd_cnst_pkg.sv.tpl
@@ -4,24 +4,28 @@
${gencmd}
<%
def make_blocked_sv_literal(hexstr, randwidth):
- """This chops the random hexstring into manageable blocks of 64 chars such that the
- lines do not get too long.
- """
- # Make all-caps and drop '0x' preamble
- hexstr = str(hexstr[2:]).upper()
- # Block width in hex chars
- blockwidth = 64
- remainder = randwidth % (4*blockwidth)
- numbits = remainder if remainder else 4*blockwidth
- idx = 0
- hexblocks = []
- while randwidth > 0:
- hexstr = hexstr[idx:]
- randwidth -= numbits
- idx = (numbits + 3) // 4
- hexblocks.append(str(numbits) + "'h" + hexstr[0:idx])
- numbits = 4*blockwidth
- return hexblocks
+ """Chop a hex string into blocks of <= 64 digits"""
+ # Convert hexstr to an actual number
+ num = int(hexstr, 16)
+ assert 0 <= num < (1 << randwidth)
+
+ mask = (1 << 256) - 1
+
+ bits_left = randwidth
+ acc = []
+ while bits_left > 0:
+ word = num & mask
+ width = min(256, bits_left)
+
+ acc.append("{nbits}'h{word:0{num_nibbles}X}"
+ .format(word=word,
+ nbits=width,
+ num_nibbles=(width + 3) // 4))
+ bits_left -= width
+ num >>= width
+
+ acc.reverse()
+ return acc
%>
package top_${top["name"]}_rnd_cnst_pkg;
