vulkan_ffv1: optimize symbol reader

This was the fastest variant tested.

Lynne committed 1 year ago

Commit fc960da1 parent defebd71 file · +5 −7Browse files

Unified · Split

libavcodec/vulkan/ffv1_dec.comp+5−7

@@ -78,13 +78,11 @@ int get_isymbol(inout RangeCoder c, uint64_t state) · 77 unmodified lines
78	78
79	79	state += 21;
80	80
81		− int a = 1 << e;
82		− int i;
83		− for (i = e - 1; i >= 9; i--)
84		− a \|= int(get_rac(c, state + 9)) << i; // 22..31
85		−
86		− for (; i >= 0; i--)
87		− a \|= int(get_rac(c, state + i)) << i; // 22..31
	81	+ int a = 1;
	82	+ for (int i = e - 1; i >= 0; i--) {
	83	+ a <<= 1;
	84	+ a \|= int(get_rac(c, state + min(i, 9))); // 22..31
	85	+ }
88	86
89	87	return get_rac(c, state - 11 + min(e, 10)) ? -a : a;
90	88	}