forgotten directories

[avr-crypto-lib.git] / noekeon / noekeon_ctr.S

diff --git a/noekeon/noekeon_ctr.S b/noekeon/noekeon_ctr.S
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+/* noekeon_ctr.S */
+/*
+    This file is part of the AVR-Crypto-Lib.
+    Copyright (C) 2008  Daniel Otte (daniel.otte@rub.de)
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/*
+ * \author  Daniel Otte
+ * \email   daniel.otte@rub.de
+ * \date    2008-08-06
+ * \license GPLv3 or later
+ * 
+ * 
+ * 
+ */
+ 
+.extern noekeon_enc
+
+/*
+ * void noekeon_ctr_next(void* buffer, const noekeon_ctr_ctx_t* ctx); 
+ */
+.global noekeon_ctr_next
+/*
+ * param buffer passed in r24:r25
+ * param ctx    passed in r22:r23
+ */
+noekeon_ctr_next:
+       /* copy counter to buffer */
+       movw r26, r24 /* copy buffer  pointer to X */
+       movw r30, r22 /* copy counter pointer to Z */  
+       ldi r16, 16
+1:     
+       ld r0, Z+
+       st X+, r0
+       dec r16
+       brne 1b
+       /* increment counter */ 
+       movw r30, r22 /* copy counter pointer to Z */  
+       ldi r17, 1
+       ldi r16, 15
+       ld  r0, Z
+       add r0, r17
+       st  Z+, r0
+1:     
+       ld  r0, Z
+       adc r0, r1
+       st  Z+, r0
+       dec r16
+       brne 1b
+       /* call encryption routine */
+       /* we can leave the first param as is, but have to adjust the second to point to the key */
+       //adiw r22, 16
+       ldi r16, 16
+       add r22, r16
+       adc r23, r0
+//     rcall noekeon_enc
+//     ret
+       rjmp noekeon_enc /* noekeon_enc will return for us */