blogpostlemireoct2021.cs

using System;
using System.Globalization;


using System.Runtime.Intrinsics.X86;
using System.Runtime.Intrinsics;
//using System.Linq;
using System.Runtime.CompilerServices;

// return true if 16 ASCII digits are found, caller is responsible
// to ensure that 16 bytes can be loaded.
[MethodImpl(MethodImplOptions.AggressiveInlining)]
unsafe  static bool is_made_of_sixteen_digits(byte* chars) {
  Vector128<sbyte> ascii0 = Vector128.Create((sbyte)47);
  Vector128<sbyte> after_ascii9 = Vector128.Create((sbyte)58);
  Vector128<sbyte> raw = Sse41.LoadDquVector128((sbyte*)chars);
  var a = Sse2.CompareGreaterThan(raw, ascii0);
  var b = Sse2.CompareLessThan(raw, after_ascii9);
  var c = Sse2.Subtract(a, b);;
  return (Sse41.TestZ(c,c));
}

// return 2 if 32 digits are found
// return 1 if 16 digits are found
// otherwise return 1
unsafe static int ParseNumberString(byte* p, byte* pend) {
  if ((p + 16 <= pend) && is_made_of_sixteen_digits(p)) {
    if((p + 32 <= pend) && is_made_of_sixteen_digits(p + 16)) {
      return 2;
    }
    return 1;
  }
  return 0;
}


// return 2 if 32 digits are found
// return 1 if 16 digits are found
// otherwise return 1
unsafe static int ParseNumberStringInline(byte* p, byte* pend) {
  if (p + 16 <= pend) {
    Vector128<sbyte> ascii0 = Vector128.Create((sbyte)47);
    Vector128<sbyte> after_ascii9 = Vector128.Create((sbyte)58);    
    Vector128<sbyte> raw = Sse41.LoadDquVector128((sbyte*)p);
    var a = Sse2.CompareGreaterThan(raw, ascii0);
    var b = Sse2.CompareLessThan(raw, after_ascii9);
    var c = Sse2.Subtract(a, b);
    if((p + 32 <= pend) && Sse41.TestZ(c,c)){
      raw = Sse41.LoadDquVector128((sbyte*)p + 16);
      a = Sse2.CompareGreaterThan(raw, ascii0);
      b = Sse2.CompareLessThan(raw, after_ascii9);
      c = Sse2.Subtract(a, b);
      if(Sse41.TestZ(c,c)) { return 2; }
    }
    return 1;
  }
  return 0;
}

​blogpostlemireoct2021.jit.asm

; Core CLR 5.0.921.35908 on x86

<Program>$.<Main>$(System.String[])
    L0000: ret

<Program>$.<<Main>$>g__is_made_of_sixteen_digits|0_0(Byte*)
    L0000: vzeroupper
    L0003: vmovupd xmm0, [<Program>$.<<Main>$>g__is_made_of_sixteen_digits|0_0(Byte*)]
    L000b: vmovupd xmm1, [<Program>$.<<Main>$>g__is_made_of_sixteen_digits|0_0(Byte*)]
    L0013: vlddqu xmm2, [ecx]
    L0017: vpcmpgtb xmm0, xmm2, xmm0
    L001b: vpcmpgtb xmm1, xmm1, xmm2
    L001f: vpsubb xmm0, xmm0, xmm1
    L0023: vptest xmm0, xmm0
    L0028: sete al
    L002b: movzx eax, al
    L002e: ret

<Program>$.<<Main>$>g__ParseNumberString|0_1(Byte*, Byte*)
    L0000: push ebp
    L0001: mov ebp, esp
    L0003: vzeroupper
    L0006: lea eax, [ecx+0x10]
    L0009: cmp eax, edx
    L000b: ja short L0071
    L000d: vmovupd xmm0, [<Program>$.<<Main>$>g__ParseNumberString|0_1(Byte*, Byte*)]
    L0015: vmovupd xmm1, [<Program>$.<<Main>$>g__ParseNumberString|0_1(Byte*, Byte*)]
    L001d: vlddqu xmm2, [ecx]
    L0021: vpcmpgtb xmm0, xmm2, xmm0
    L0025: vpcmpgtb xmm1, xmm1, xmm2
    L0029: vpsubb xmm0, xmm0, xmm1
    L002d: vptest xmm0, xmm0
    L0032: jne short L0071
    L0034: lea eax, [ecx+0x20]
    L0037: cmp eax, edx
    L0039: ja short L006a
    L003b: vmovupd xmm0, [<Program>$.<<Main>$>g__ParseNumberString|0_1(Byte*, Byte*)]
    L0043: vmovupd xmm1, [<Program>$.<<Main>$>g__ParseNumberString|0_1(Byte*, Byte*)]
    L004b: vlddqu xmm2, [ecx+0x10]
    L0050: vpcmpgtb xmm0, xmm2, xmm0
    L0054: vpcmpgtb xmm1, xmm1, xmm2
    L0058: vpsubb xmm0, xmm0, xmm1
    L005c: vptest xmm0, xmm0
    L0061: jne short L006a
    L0063: mov eax, 2
    L0068: pop ebp
    L0069: ret
    L006a: mov eax, 1
    L006f: pop ebp
    L0070: ret
    L0071: xor eax, eax
    L0073: pop ebp
    L0074: ret

<Program>$.<<Main>$>g__ParseNumberStringInline|0_2(Byte*, Byte*)
    L0000: push ebp
    L0001: mov ebp, esp
    L0003: vzeroupper
    L0006: lea eax, [ecx+0x10]
    L0009: cmp eax, edx
    L000b: ja short L0061
    L000d: vmovupd xmm0, [<Program>$.<<Main>$>g__ParseNumberStringInline|0_2(Byte*, Byte*)]
    L0015: vmovupd xmm1, [<Program>$.<<Main>$>g__ParseNumberStringInline|0_2(Byte*, Byte*)]
    L001d: vlddqu xmm2, [ecx]
    L0021: vpcmpgtb xmm3, xmm2, xmm0
    L0025: vpcmpgtb xmm2, xmm1, xmm2
    L0029: vpsubb xmm4, xmm3, xmm2
    L002d: lea eax, [ecx+0x20]
    L0030: cmp eax, edx
    L0032: ja short L005a
    L0034: vptest xmm4, xmm4
    L0039: jne short L005a
    L003b: vlddqu xmm2, [ecx+0x10]
    L0040: vpcmpgtb xmm3, xmm2, xmm0
    L0044: vpcmpgtb xmm2, xmm1, xmm2
    L0048: vpsubb xmm4, xmm3, xmm2
    L004c: vptest xmm4, xmm4
    L0051: jne short L005a
    L0053: mov eax, 2
    L0058: pop ebp
    L0059: ret
    L005a: mov eax, 1
    L005f: pop ebp
    L0060: ret
    L0061: xor eax, eax
    L0063: pop ebp
    L0064: ret

​​.sharplab.json

{
    "version": 1,
    "target": "JIT ASM",
    "mode": "Release"
}