1	import Base
2	import ./kernel_tile.bend as Tile
3	
4	# Four independent output rows share one input tile: half of an eight-row
5	# weight block. This is a fixed product, not an indexed type or a list.
6	type Rows<-Element: Data> is Data:
7	  Rows{r0: Element,r1: Element,r2: Element,r3: Element}
8	
9	def filled(~Element: Data,+value: Element) -> Rows<Element>:
10	  Rows{value,value,value,value}
11	
12	def first(~Element: Data,values: Rows<Element>) -> Element:
13	  Rows{a,b,c,d} = values
14	  a
15	
16	def second(~Element: Data,values: Rows<Element>) -> Element:
17	  Rows{a,b,c,d} = values
18	  b
19	
20	def third(~Element: Data,values: Rows<Element>) -> Element:
21	  Rows{a,b,c,d} = values
22	  c
23	
24	def fourth(~Element: Data,values: Rows<Element>) -> Element:
25	  Rows{a,b,c,d} = values
26	  d
27	
28	# The lower or upper four rows of an eight-row weight tile.
29	def half(upper: Bool,tile: Tile.Tile8) -> Rows<F32>:
30	  match upper:
31	    case False{}:
32	      Tile.Tile{a,b,c,d,e,f,g,h} = tile
33	      Rows{a,b,c,d}
34	    case True{}:
35	      Tile.Tile{a,b,c,d,e,f,g,h} = tile
36	      Rows{e,f,g,h}
37	
38	def map(~Element: Data,~Input: Data,~Weight: Data,
39	  ~update: Element -> Input -> Weight -> Element,
40	  accumulators: Rows<Element>,+input: Input,weights: Rows<Weight>) -> Rows<Element>:
41	  Rows{a0,a1,a2,a3} = accumulators
42	  Rows{w0,w1,w2,w3} = weights
43	  Rows{update(a0,input,w0),update(a1,input,w1),update(a2,input,w2),update(a3,input,w3)}