Added analysis script used for investigating direct color DMA timing

1 files changed, 60 insertions, 0 deletions

diff --git a/analyze_olp.py b/analyze_olp.py
new file mode 100755
index 0000000..652edc4
--- /dev/null
+++ b/analyze_olp.py
@@ -0,0 +1,60 @@
+#!/usr/bin/env python
+
+from zipfile import ZipFile
+from sys import exit, argv
+
+def detect_rise(last, sample, bit):
+	mask = 1 << bit
+	return (not last & mask) and (sample & mask)
+
+def detect_fall(last, sample, bit):
+	mask = 1 << bit
+	return (last & mask) and (not sample & mask)
+
+def detect_high(sample, bit):
+	mask = 1 << bit
+	return sample & mask
+
+def detect_low(sample, bit):
+	mask = 1 << bit
+	return not sample & mask
+
+def analyze_delays(chanmap, datafile):
+	m68k_clk = chanmap['M68K CLK']
+	m_as = chanmap['!AS']
+	last = False
+	clks = 0
+	as_start = 0
+	for line in datafile.readlines():
+		line = line.strip()
+		if line and not line.startswith(';'):
+			sample,_,num = line.partition('@')
+			sample = int(sample, 16)
+			if not (last is False):
+				if detect_rise(last, sample, m68k_clk):
+					clks = clks + 1
+				if detect_rise(last, sample, m_as):
+					as_clks  = clks - as_start
+					if as_clks > 2:
+						print '!AS held for', as_clks, 'cycles starting (delay of ' + str(as_clks - 2) + ') at', as_start, 'and ending at', clks
+				elif detect_fall(last, sample, m_as):
+					as_start = clks
+			last = sample
+
+def main(args):
+	if len(args) < 2:
+		print 'Usage: analyze_olp.py filename'
+		exit(1)
+	olpfile = ZipFile(args[1], "r")
+	channelfile = olpfile.open('channel.labels')
+	channels = [line.strip() for line in channelfile.readlines()]
+	channelfile.close()
+	chanmap = {}
+	for i in xrange(0, len(channels)):
+		chanmap[channels[i]] = i
+	datafile = olpfile.open('data.ols')
+	analyze_delays(chanmap, datafile)
+
+
+if __name__ == '__main__':
+	main(argv)