From 274518e5d989ff2ba83493825ee2531c947d04e3 Mon Sep 17 00:00:00 2001
From: henryk <henryk@6dc7ffe9-61d6-0310-9af1-9938baff3ed1>
Date: Mon, 10 Mar 2008 10:49:36 +0000
Subject: Further optimizations, is now down to 1450 MCK/2 cycles for a 7 bit
frame, that should be real-time capable
git-svn-id: https://svn.openpcd.org:2342/trunk@449 6dc7ffe9-61d6-0310-9af1-9938baff3ed1
---
openpicc/application/iso14443a_diffmiller.c | 68 ++++++++++++-----------------
1 file changed, 29 insertions(+), 39 deletions(-)
(limited to 'openpicc/application')
diff --git a/openpicc/application/iso14443a_diffmiller.c b/openpicc/application/iso14443a_diffmiller.c
index cc895df..a5acfc8 100644
--- a/openpicc/application/iso14443a_diffmiller.c
+++ b/openpicc/application/iso14443a_diffmiller.c
@@ -113,7 +113,6 @@ struct diffmiller_state _state;
inline void start_frame(struct diffmiller_state * const state)
{
- state->counter=0;
state->byte=0;
state->parity=0;
state->crc=0x6363;
@@ -128,10 +127,10 @@ inline void start_frame(struct diffmiller_state * const state)
}
static inline void append_to_frame(struct diffmiller_state *const state,
- const u_int8_t byte, const u_int8_t parity, const u_int8_t valid_bits) {
+ u_int8_t byte, const u_int8_t parity, const u_int8_t valid_bits) {
iso14443_frame * const f = state->frame;
-
+
if(f->numbytes >= sizeof(f->data)/sizeof(f->data[0])-1) { /* -1, because the last byte may be half filled */
state->flags.overflow = 1;
return;
@@ -146,17 +145,20 @@ static inline void append_to_frame(struct diffmiller_state *const state,
if(valid_bits == 8) {
f->numbytes++;
+ byte=(byte ^ state->crc)&0xFF;
+ byte=(byte ^ byte<<4)&0xFF;
+ state->crc=((state->crc>>8)^(byte<<8)^(byte<<3)^(byte>>4))&0xFFFF;
} else {
f->numbits += valid_bits;
}
}
-static inline void end_frame(struct diffmiller_state * const state)
+static inline void end_frame(struct diffmiller_state * const state, const u_int32_t counter)
{
if(state->frame != NULL) {
- if(state->counter > 0) {
- append_to_frame(state, state->byte, 0, state->counter);
+ if(counter > 0) {
+ append_to_frame(state, state->byte, 0, counter);
}
if(!state->crc)
@@ -168,50 +170,34 @@ static inline void end_frame(struct diffmiller_state * const state)
}
}
-static inline void Miller_Bit(struct diffmiller_state * const state, const int bit_value)
-{
-
- if(state->counter<8) {
- state->byte=state->byte | (bit_value<<state->counter);
- if(bit_value)
- state->parity++;
- } else DEBUGP((((~state->parity)&1)==bit_value) ? " ":"!" );
-
- if(++state->counter==9) {
- state->counter=0;
- append_to_frame(state, state->byte, bit_value, 8);
-
- //DEBUGP(" ==0x%02X\n",byte);
-
- state->byte=(state->byte ^ state->crc)&0xFF;
- state->byte=(state->byte ^ state->byte<<4)&0xFF;
- state->crc=((state->crc>>8)^(state->byte<<8)^(state->byte<<3)^(state->byte>>4))&0xFFFF;
-
- //printf(" [%04X]\n",crc);
-
- state->byte=0;
- state->parity=0;
- }
-}
-
#define PRINT_BIT(a) if(0){(void)a;}
//#define PRINT_BIT(a) usb_print_string(a)
#define DO_BIT_0 { \
- Miller_Bit(state, 0); \
+ if(++counter==9) { \
+ append_to_frame(state, state->byte, 0, 8); \
+ counter=state->byte=state->parity=0; \
+ } \
PRINT_BIT(" 0"); \
- }
+}
#define DO_BIT_1 { \
- Miller_Bit(state, 1); \
+ if(counter<8) { \
+ state->byte |= (1<<counter); \
+ state->parity ^= 1; \
+ } \
+ if(++counter==9) { \
+ append_to_frame(state, state->byte, 1, 8); \
+ counter=state->byte=state->parity=0; \
+ } \
PRINT_BIT(" 1"); \
- }
+}
#define DO_SYMBOL_X \
if(!in_frame) { \
if(last_bit == BIT_0) DO_BIT_0; \
error = 1; \
- end_frame(state); \
+ end_frame(state, counter); \
PRINT_BIT(" ERROR\n"); \
last_bit = BIT_ERROR; \
in_frame = 0; \
@@ -225,13 +211,13 @@ static inline void Miller_Bit(struct diffmiller_state * const state, const int b
if(!in_frame) { \
if(last_bit == BIT_0) DO_BIT_0; \
error = 1; \
- end_frame(state); \
+ end_frame(state, counter); \
PRINT_BIT(" ERROR\n"); \
last_bit = BIT_ERROR; \
in_frame = 0; \
} else { \
if(last_bit == BIT_0) { \
- end_frame(state); \
+ end_frame(state, counter); \
PRINT_BIT(" EOF\n"); \
last_bit = BIT_EOF; \
in_frame = 0; \
@@ -243,6 +229,7 @@ static inline void Miller_Bit(struct diffmiller_state * const state, const int b
#define DO_SYMBOL_Z \
if(!in_frame) { \
if(last_bit == BIT_0) DO_BIT_0; \
+ counter = 0; \
start_frame(state); \
PRINT_BIT("SOF"); \
in_frame = 1; \
@@ -265,6 +252,7 @@ int iso14443a_decode_diffmiller(struct diffmiller_state * const state, iso14443_
enum bit last_bit = state->last_bit;
int in_frame = state->flags.in_frame;
int error = state->flags.error;
+ int counter = state->counter;
for(; *offset < buflen; ) {
int delta;
@@ -322,6 +310,7 @@ int iso14443a_decode_diffmiller(struct diffmiller_state * const state, iso14443_
state->flags.frame_finished = 0;
state->old_state = old_state;
state->last_bit = last_bit;
+ state->counter = counter;
state->flags.in_frame = in_frame;
state->flags.error = error;
performance_set_checkpoint("frame finished");
@@ -331,6 +320,7 @@ int iso14443a_decode_diffmiller(struct diffmiller_state * const state, iso14443_
state->old_state = old_state;
state->last_bit = last_bit;
+ state->counter = counter;
state->flags.in_frame = in_frame;
state->flags.error = error;
--
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