libass assembler code sanity check

libass-asm-test.ass

[Script Info]
ScriptType: v4.00+
PlayResX: 1280
PlayResY: 720
ScaledBorderAndShadow: yes
YCbCr Matrix: None

[V4+ Styles]
Format: Name, Fontname, Fontsize, PrimaryColour, SecondaryColour, OutlineColour, BackColour, Bold, Italic, Underline, StrikeOut, ScaleX, ScaleY, Spacing, Angle, BorderStyle, Outline, Shadow, Alignment, MarginL, MarginR, MarginV, Encoding
Style: Default,Arial,18,&H00000000,&H00000000,&H00000000,&H00000000,-1,0,0,0,100,100,0,0,1,0,0,2,0,0,50,1

[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.00,0:00:10.00,Default,,0,0,0,,{\pos(0,0)\an7\c&HFFFF00&\p1}m 0 0 l 1280 0 1280 720 0 720
Dialogue: 1,0:00:00.00,0:00:10.00,Default,,0,0,0,,A quick brown fox jumps over the lazy dog.
Dialogue: 1,0:00:00.00,0:00:10.00,Default,,0,0,0,,{\blur20\p1}m 0 0 l 100 100 200 0 200 200 0 200
Dialogue: 1,0:00:00.00,0:00:10.00,Default,,0,0,0,,{\be20\p1}m 0 0 l 100 100 200 0 200 200 0 200
Dialogue: 1,0:00:00.00,0:00:10.00,Default,,0,0,0,,{\clip(m 0 0 l 640 0 640 720 0 720)\p1}m 0 0 l 100 100 200 0 200 200 0 200