Use max-scan instead of plus-scan for 1-byte Bins table

This commit is contained in:
Marshall Lochbaum 2023-07-07 15:41:04 -04:00
parent 8054597004
commit f36dc7adba

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@ -147,7 +147,6 @@ def bins_lookup{I, T, up, w:*T, wn:u64, x:*T, xn:u64, rp:*void} = {
def bins_lookup{I==i8, T==i8, up, w:*T, wn:u64, x:*T, xn:u64, rp:*void & hasarch{'AVX2'}} = {
assert{wn < 128} # Total must fit in i8
def T = i8
def vl = 32
def V = [vl]T; def H = v_half{V}
def U = [vl]u8
@ -155,10 +154,7 @@ def bins_lookup{I==i8, T==i8, up, w:*T, wn:u64, x:*T, xn:u64, rp:*void & hasarch
t0:*i8 = copy{256,0}
t:*i8 = t0 + 128
@for (w over wn) store{t, w, 1+load{t, w}}
def plus_scan{tab, len} = {
s:i8=0; @for_dir{up} (tab over len) { s += tab; tab = s }
}
@for (w over j to wn) store{t, w, j+1}
# Convert to bit table
def no_bittab = makelabel{}; def done = makelabel{}
@ -175,7 +171,7 @@ def bins_lookup{I==i8, T==i8, up, w:*T, wn:u64, x:*T, xn:u64, rp:*void & hasarch
if (nu > maxu) goto{no_bittab}
# We'll subtract 1 when indexing so the initial 0 isn't needed
tui:*i8 = copy{maxu, 0}; i:T = 0
@for (tui over promote{u64,nu}) { i += load{t, load{w, i}}; tui = i }
@for (tui over promote{u64,nu}) { i = load{t, load{w, i}}; tui = i }
def tv = bind{load, *V~~tui}
ui = tv{0}
if (nu > 16) ui1 = shuf{[4]u64, ui, 4b3232}
@ -198,7 +194,7 @@ def bins_lookup{I==i8, T==i8, up, w:*T, wn:u64, x:*T, xn:u64, rp:*void & hasarch
def sel_m = getsel{make{H, merge{ms - 256*(ms>127), 8**0}}}
# Exact values for multiples of 8
store{*U~~t0, 0, vpopc{vb}}
plus_scan{t0, 256/8}
st:i8=0; @for_dir{up} (t0 over 256/8) { st += t0; t0 = st }
def sel_c = getsel{swap{load{*V~~t0, 0} - V**dup}}
# Top 5 bits select bytes from tables; bottom 3 select from mask
bot3 := U**0x07
@ -222,7 +218,7 @@ def bins_lookup{I==i8, T==i8, up, w:*T, wn:u64, x:*T, xn:u64, rp:*void & hasarch
goto{done}
setlabel{no_bittab}
plus_scan{t0, 256}
max_scan{I, up}(t0, 256)
@for (res, x over xn) res = load{t, x}
setlabel{done}
}