Added bitrev instruction for 32 and 64 bit integers (#486)
This commit is contained in:
Aaron Power
@@ -26,6 +26,7 @@ from .instructions import rotl, rotl_imm, rotr, rotr_imm
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from .instructions import f32const, f64const
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from .instructions import store, load
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from .instructions import br_table
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from .instructions import bitrev
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from cdsl.ast import Var
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from cdsl.xform import Rtl, XFormGroup
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@@ -91,17 +92,35 @@ y = Var('y')
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a = Var('a')
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a1 = Var('a1')
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a2 = Var('a2')
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a3 = Var('a3')
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a4 = Var('a4')
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b = Var('b')
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b1 = Var('b1')
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b2 = Var('b2')
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b3 = Var('b3')
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b4 = Var('b4')
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b_in = Var('b_in')
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b_int = Var('b_int')
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c = Var('c')
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c1 = Var('c1')
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c2 = Var('c2')
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c3 = Var('c3')
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c4 = Var('c4')
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c_in = Var('c_in')
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c_int = Var('c_int')
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d = Var('d')
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d1 = Var('d1')
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d2 = Var('d2')
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d3 = Var('d3')
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d4 = Var('d4')
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e = Var('e')
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e1 = Var('e1')
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e2 = Var('e2')
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e3 = Var('e3')
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e4 = Var('e4')
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f = Var('f')
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f1 = Var('f1')
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f2 = Var('f2')
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xl = Var('xl')
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xh = Var('xh')
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yl = Var('yl')
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@@ -382,6 +401,115 @@ expand.legalize(
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a << bxor(x, y)
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))
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# Expand bitrev
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# Adapted from Stack Overflow.
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# https://stackoverflow.com/questions/746171/most-efficient-algorithm-for-bit-reversal-from-msb-lsb-to-lsb-msb-in-c
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widen.legalize(
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a << bitrev.i8(x),
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Rtl(
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a1 << band_imm(x, imm64(0xaa)),
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a2 << ushr_imm(a1, imm64(1)),
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a3 << band_imm(x, imm64(0x55)),
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a4 << ishl_imm(a3, imm64(1)),
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b << bor(a2, a4),
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b1 << band_imm(b, imm64(0xcc)),
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b2 << ushr_imm(b1, imm64(2)),
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b3 << band_imm(b, imm64(0x33)),
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b4 << ushr_imm(b3, imm64(2)),
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c << bor(b2, b4),
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c1 << band_imm(c, imm64(0xf0)),
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c2 << ushr_imm(c1, imm64(4)),
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c3 << band_imm(c, imm64(0x0f)),
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c4 << ishl_imm(c3, imm64(4)),
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a << bor(c2, c4),
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))
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widen.legalize(
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a << bitrev.i16(x),
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Rtl(
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a1 << band_imm(x, imm64(0xaaaa)),
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a2 << ushr_imm(a1, imm64(1)),
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a3 << band_imm(x, imm64(0x5555)),
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a4 << ishl_imm(a3, imm64(1)),
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b << bor(a2, a4),
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b1 << band_imm(b, imm64(0xcccc)),
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b2 << ushr_imm(b1, imm64(2)),
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b3 << band_imm(b, imm64(0x3333)),
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b4 << ushr_imm(b3, imm64(2)),
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c << bor(b2, b4),
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c1 << band_imm(c, imm64(0xf0f0)),
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c2 << ushr_imm(c1, imm64(4)),
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c3 << band_imm(c, imm64(0x0f0f)),
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c4 << ishl_imm(c3, imm64(4)),
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d << bor(c2, c4),
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d1 << band_imm(d, imm64(0xff00)),
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d2 << ushr_imm(d1, imm64(8)),
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d3 << band_imm(d, imm64(0x00ff)),
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d4 << ishl_imm(d3, imm64(8)),
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a << bor(d2, d4),
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))
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expand.legalize(
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a << bitrev.i32(x),
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Rtl(
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a1 << band_imm(x, imm64(0xaaaaaaaa)),
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a2 << ushr_imm(a1, imm64(1)),
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a3 << band_imm(x, imm64(0x55555555)),
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a4 << ishl_imm(a3, imm64(1)),
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b << bor(a2, a4),
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b1 << band_imm(b, imm64(0xcccccccc)),
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b2 << ushr_imm(b1, imm64(2)),
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b3 << band_imm(b, imm64(0x33333333)),
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b4 << ushr_imm(b3, imm64(2)),
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c << bor(b2, b4),
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c1 << band_imm(c, imm64(0xf0f0f0f0)),
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c2 << ushr_imm(c1, imm64(4)),
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c3 << band_imm(c, imm64(0x0f0f0f0f)),
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c4 << ishl_imm(c3, imm64(4)),
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d << bor(c2, c4),
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d1 << band_imm(d, imm64(0xff00ff00)),
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d2 << ushr_imm(d1, imm64(8)),
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d3 << band_imm(d, imm64(0x00ff00ff)),
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d4 << ishl_imm(d3, imm64(8)),
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e << bor(d2, d4),
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e1 << ushr_imm(e, imm64(16)),
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e2 << ishl_imm(e, imm64(16)),
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a << bor(e1, e2),
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))
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expand.legalize(
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a << bitrev.i64(x),
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Rtl(
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a1 << band_imm(x, imm64(0xaaaaaaaaaaaaaaaa)),
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a2 << ushr_imm(a1, imm64(1)),
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a3 << band_imm(x, imm64(0x5555555555555555)),
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a4 << ishl_imm(a3, imm64(1)),
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b << bor(a2, a4),
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b1 << band_imm(b, imm64(0xcccccccccccccccc)),
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b2 << ushr_imm(b1, imm64(2)),
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b3 << band_imm(b, imm64(0x3333333333333333)),
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b4 << ushr_imm(b3, imm64(2)),
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c << bor(b2, b4),
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c1 << band_imm(c, imm64(0xf0f0f0f0f0f0f0f0)),
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c2 << ushr_imm(c1, imm64(4)),
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c3 << band_imm(c, imm64(0x0f0f0f0f0f0f0f0f)),
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c4 << ishl_imm(c3, imm64(4)),
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d << bor(c2, c4),
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d1 << band_imm(d, imm64(0xff00ff00ff00ff00)),
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d2 << ushr_imm(d1, imm64(8)),
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d3 << band_imm(d, imm64(0x00ff00ff00ff00ff)),
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d4 << ishl_imm(d3, imm64(8)),
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e << bor(d2, d4),
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e1 << band_imm(e, imm64(0xffff0000ffff0000)),
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e2 << ushr_imm(e1, imm64(16)),
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e3 << band_imm(e, imm64(0x0000ffff0000ffff)),
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e4 << ishl_imm(e3, imm64(16)),
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f << bor(e2, e4),
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f1 << ushr_imm(f, imm64(32)),
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f2 << ishl_imm(f, imm64(32)),
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a << bor(f1, f2),
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))
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# Floating-point sign manipulations.
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for ty, minus_zero in [
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(types.f32, f32const(ieee32.bits(0x80000000))),
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