From e4fa00258cd920d4ea91b024ee007f5b44bac196 Mon Sep 17 00:00:00 2001
From: Paul Selkirk <paul@psgd.org>
Date: Tue, 11 Sep 2018 19:01:19 -0400
Subject: Track Joachim's latest keywrap core - unroll bank-switched memory
 into a number of core register blocks.

---
 aes_keywrap.c | 27 ++++++++-------------------
 1 file changed, 8 insertions(+), 19 deletions(-)

(limited to 'aes_keywrap.c')

diff --git a/aes_keywrap.c b/aes_keywrap.c
index 8ef018b..a3e223f 100644
--- a/aes_keywrap.c
+++ b/aes_keywrap.c
@@ -144,8 +144,10 @@ static hal_error_t do_keywrap_core(const hal_core_t *core, uint8_t * const C, co
 
   hal_assert(core != NULL && C != NULL && n > 0);
 
-  /* The core is limited to 128 banks of 512 bytes/64 blocks */
-  if (n == 0 || n > 128 * 64)
+  /* n is the number of 64-bit (8-byte) blocks in the input.
+   * KEYWRAP_LEN_R_DATA is the number of 4-byte data registers in the core.
+   */
+  if (n == 0 || n > KEYWRAP_LEN_R_DATA * 2)
     return HAL_ERROR_BAD_ARGUMENTS;
 
   /* write the AIV to A */
@@ -157,16 +159,9 @@ static hal_error_t do_keywrap_core(const hal_core_t *core, uint8_t * const C, co
   if ((err = hal_io_write(core, KEYWRAP_ADDR_RLEN, (const uint8_t *)&nn, 4)) != HAL_OK)
     return err;
 
-  /* write the data to R_DATA, with bank-switching as necessary */
-  for (size_t bank = 0; 64 * bank < n; ++bank) {
-    uint32_t bb = htonl(bank);
-    if ((err = hal_io_write(core, KEYWRAP_ADDR_R_BANK, (const uint8_t *)&bb, 4)) != HAL_OK)
-      return err;
-    /* R_DATA is 128 32-bit registers, so 64 64-bit blocks or 512 bytes. */
-    size_t len = min(n - 64 * bank, 64) * 8;
-    if ((err = hal_io_write(core, KEYWRAP_ADDR_R_DATA0, (C + 512 * bank + 8), len)) != HAL_OK)
+  /* write the data to R_DATA */
+  if ((err = hal_io_write(core, KEYWRAP_ADDR_R_DATA, C + 8, 8 * n)) != HAL_OK)
       return err;
-  }
 
   /* start the wrap/unwrap operation, and wait for it to complete */
   if ((err = hal_io_next(core)) != HAL_OK ||
@@ -177,15 +172,9 @@ static hal_error_t do_keywrap_core(const hal_core_t *core, uint8_t * const C, co
   if ((err = hal_io_read(core, KEYWRAP_ADDR_A0, C, 8)) != HAL_OK)
     return err;
 
-  /* read the data from R_DATA, with bank-switching as necessary */
-  for (size_t bank = 0; 64 * bank < n; ++bank) {
-    uint32_t bb = htonl(bank);
-    if ((err = hal_io_write(core, KEYWRAP_ADDR_R_BANK, (const uint8_t *)&bb, 4)) != HAL_OK)
+  /* read the data to R_DATA */
+  if ((err = hal_io_read(core, KEYWRAP_ADDR_R_DATA, C + 8, 8 * n)) != HAL_OK)
       return err;
-    size_t len = min(n - 64 * bank, 64) * 8;
-    if ((err = hal_io_read(core, KEYWRAP_ADDR_R_DATA0, (C + 512 * bank + 8), len)) != HAL_OK)
-      return err;
-  }
 
   return HAL_OK;
 }
-- 
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