From 2fcd7c22852436c3226de9007e88cb305cce1b00 Mon Sep 17 00:00:00 2001 From: Uwe Hermann Date: Wed, 11 Jul 2012 22:19:31 +0200 Subject: srd: Performance improvements for various PDs. Ignore/skip identical samples in most (low-level) PDs, as we're usually (but not necessarily always) only interested in pin changes. This yields a significant performance improvement for the PDs. The mechanism was already used in the 'i2s', 'jtag', and 'lpc' PDs, but not yet in all supported low-level decoders. The following PDs now also use this mechanism: 'dcf77', 'i2c', 'spi', 'uart', and 'usb_signalling'. Thanks Lars-Peter Clausen for bringing this to our attention. --- decoders/usb_signalling/usb_signalling.py | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'decoders/usb_signalling') diff --git a/decoders/usb_signalling/usb_signalling.py b/decoders/usb_signalling/usb_signalling.py index 512703d..3272cbf 100644 --- a/decoders/usb_signalling/usb_signalling.py +++ b/decoders/usb_signalling/usb_signalling.py @@ -67,6 +67,7 @@ class Decoder(srd.Decoder): self.scount = 0 self.packet = '' self.syms = [] + self.oldpins = None def start(self, metadata): self.samplerate = metadata['samplerate'] @@ -77,13 +78,18 @@ class Decoder(srd.Decoder): pass def decode(self, ss, es, data): - for (self.samplenum, (dp, dm)) in data: + for (self.samplenum, pins) in data: # Note: self.samplenum is the absolute sample number, whereas # self.scount only counts the number of samples since the # last change in the D+/D- lines. self.scount += 1 + # Ignore identical samples early on (for performance reasons). + if self.oldpins == pins: + continue + self.oldpins, (dp, dm) = pins, pins + if self.options['signalling'] == 'low-speed': sym = symbols_ls[dp, dm] elif self.options['signalling'] == 'full-speed': -- cgit v1.2.3-70-g09d2