Hoernchen has uploaded this change for review. (
https://gerrit.osmocom.org/c/osmo-ccid-firmware/+/40721?usp=email )
Change subject: 7816 fsm: drop inverse convention lut for arm
......................................................................
7816 fsm: drop inverse convention lut for arm
3 instructions is more reliable than precious bytes and awfully slow memory.
Change-Id: I1c6f1c4b733074201cb02c0b9e7cf80a9f8dca7c
---
M ccid_common/iso7816_fsm.c
1 file changed, 21 insertions(+), 1 deletion(-)
git pull ssh://gerrit.osmocom.org:29418/osmo-ccid-firmware
refs/changes/21/40721/1
diff --git a/ccid_common/iso7816_fsm.c b/ccid_common/iso7816_fsm.c
index 0aa9571..269feee 100644
--- a/ccid_common/iso7816_fsm.c
+++ b/ccid_common/iso7816_fsm.c
@@ -149,6 +149,19 @@
static struct osmo_fsm tpdu_fsm;
static struct osmo_fsm pps_fsm;
+#if defined(__arm__)
+#define invert_flip_uint8(XX)
\
+ do {
\
+ _Static_assert(__builtin_types_compatible_p(__typeof__(XX),
uint8_t), \
+ "invert_flip_uint8 argument must be uint8_t");
\
+ /* xor to flip done by the compiler, since it might be a mvns
instead of eor if convenient, so don't force it manually*/ \
+ XX = ~XX;
\
+ __asm__ volatile("rbit %0, %0 \n\t"
\
+ "uxtb.w %0, %0, ror #24 \n\t"
\
+ : "+r"(XX)::/* lsr clobbers cc, uxtb does not
*/ \
+ );
\
+ } while (0);
+#else
/* look-up table for bit-wise inversion to convert from "inverse convention"
to normal */
static const uint8_t convention_convert_lut[256] = {
0xff, 0x7f, 0xbf, 0x3f, 0xdf, 0x5f, 0x9f, 0x1f, 0xef, 0x6f, 0xaf, 0x2f,
0xcf, 0x4f, 0x8f, 0x0f,
@@ -168,6 +181,13 @@
0xf8, 0x78, 0xb8, 0x38, 0xd8, 0x58, 0x98, 0x18, 0xe8, 0x68, 0xa8, 0x28,
0xc8, 0x48, 0x88, 0x08,
0xf0, 0x70, 0xb0, 0x30, 0xd0, 0x50, 0x90, 0x10, 0xe0, 0x60, 0xa0, 0x20,
0xc0, 0x40, 0x80, 0x00,
};
+#define invert_flip_uint8(XX)
\
+ do {
\
+ _Static_assert(__builtin_types_compatible_p(__typeof__(XX),
uint8_t), \
+ "invert_flip_uint8 argument must be uint8_t");
\
+ XX = convention_convert_lut[XX];
\
+ } while (0);
+#endif
struct atr_fsm_priv {
uint8_t hist_len; /*!< store the number of expected historical
bytes */
@@ -656,7 +676,7 @@
/* apply inverse convention */
if (ip->convention_convert)
- byte = convention_convert_lut[byte];
+ invert_flip_uint8(byte);
return byte;
}
--
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Gerrit-MessageType: newchange
Gerrit-Project: osmo-ccid-firmware
Gerrit-Branch: master
Gerrit-Change-Id: I1c6f1c4b733074201cb02c0b9e7cf80a9f8dca7c
Gerrit-Change-Number: 40721
Gerrit-PatchSet: 1
Gerrit-Owner: Hoernchen <[email protected]>
