xref: /aosp_15_r20/external/lzma/C/Bra.c (revision f6dc9357d832569d4d1f5d24eacdb3935a1ae8e6)

/* Bra.c -- Branch converters for RISC code
2024-01-20 : Igor Pavlov : Public domain */

#include "Precomp.h"

#include "Bra.h"
#include "RotateDefs.h"
#include "CpuArch.h"

#if defined(MY_CPU_SIZEOF_POINTER) \
    && ( MY_CPU_SIZEOF_POINTER == 4 \
      || MY_CPU_SIZEOF_POINTER == 8)
  #define BR_CONV_USE_OPT_PC_PTR
#endif

#ifdef BR_CONV_USE_OPT_PC_PTR
#define BR_PC_INIT  pc -= (UInt32)(SizeT)p;
#define BR_PC_GET   (pc + (UInt32)(SizeT)p)
#else
#define BR_PC_INIT  pc += (UInt32)size;
#define BR_PC_GET   (pc - (UInt32)(SizeT)(lim - p))
// #define BR_PC_INIT
// #define BR_PC_GET   (pc + (UInt32)(SizeT)(p - data))
#endif

#define BR_CONVERT_VAL(v, c) if (encoding) v += c; else v -= c;
// #define BR_CONVERT_VAL(v, c) if (!encoding) c = (UInt32)0 - c; v += c;

#define Z7_BRANCH_CONV(name) z7_ ## name

#define Z7_BRANCH_FUNC_MAIN(name) \
static \
Z7_FORCE_INLINE \
Z7_ATTRIB_NO_VECTOR \
Byte *Z7_BRANCH_CONV(name)(Byte *p, SizeT size, UInt32 pc, int encoding)

#define Z7_BRANCH_FUNC_IMP(name, m, encoding) \
Z7_NO_INLINE \
Z7_ATTRIB_NO_VECTOR \
Byte *m(name)(Byte *data, SizeT size, UInt32 pc) \
  { return Z7_BRANCH_CONV(name)(data, size, pc, encoding); } \

#ifdef Z7_EXTRACT_ONLY
#define Z7_BRANCH_FUNCS_IMP(name) \
  Z7_BRANCH_FUNC_IMP(name, Z7_BRANCH_CONV_DEC_2, 0)
#else
#define Z7_BRANCH_FUNCS_IMP(name) \
  Z7_BRANCH_FUNC_IMP(name, Z7_BRANCH_CONV_DEC_2, 0) \
  Z7_BRANCH_FUNC_IMP(name, Z7_BRANCH_CONV_ENC_2, 1)
#endif

#if defined(__clang__)
#define BR_EXTERNAL_FOR
#define BR_NEXT_ITERATION  continue;
#else
#define BR_EXTERNAL_FOR    for (;;)
#define BR_NEXT_ITERATION  break;
#endif

#if defined(__clang__) && (__clang_major__ >= 8) \
  || defined(__GNUC__) && (__GNUC__ >= 1000) \
  // GCC is not good for __builtin_expect() here
  /* || defined(_MSC_VER) && (_MSC_VER >= 1920) */
  // #define Z7_unlikely [[unlikely]]
  // #define Z7_LIKELY(x)   (__builtin_expect((x), 1))
  #define Z7_UNLIKELY(x) (__builtin_expect((x), 0))
  // #define Z7_likely [[likely]]
#else
  // #define Z7_LIKELY(x)   (x)
  #define Z7_UNLIKELY(x) (x)
  // #define Z7_likely
#endif


Z7_BRANCH_FUNC_MAIN(BranchConv_ARM64)
{
  // Byte *p = data;
  const Byte *lim;
  const UInt32 flag = (UInt32)1 << (24 - 4);
  const UInt32 mask = ((UInt32)1 << 24) - (flag << 1);
  size &= ~(SizeT)3;
  // if (size == 0) return p;
  lim = p + size;
  BR_PC_INIT
  pc -= 4;  // because (p) will point to next instruction

  BR_EXTERNAL_FOR
  {
    // Z7_PRAGMA_OPT_DISABLE_LOOP_UNROLL_VECTORIZE
    for (;;)
    {
      UInt32 v;
      if Z7_UNLIKELY(p == lim)
        return p;
      v = GetUi32a(p);
      p += 4;
      if Z7_UNLIKELY(((v - 0x94000000) & 0xfc000000) == 0)
      {
        UInt32 c = BR_PC_GET >> 2;
        BR_CONVERT_VAL(v, c)
        v &= 0x03ffffff;
        v |= 0x94000000;
        SetUi32a(p - 4, v)
        BR_NEXT_ITERATION
      }
      // v = rotlFixed(v, 8);  v += (flag << 8) - 0x90;  if Z7_UNLIKELY((v & ((mask << 8) + 0x9f)) == 0)
      v -= 0x90000000;  if Z7_UNLIKELY((v & 0x9f000000) == 0)
      {
        UInt32 z, c;
        // v = rotrFixed(v, 8);
        v += flag; if Z7_UNLIKELY(v & mask) continue;
        z = (v & 0xffffffe0) | (v >> 26);
        c = (BR_PC_GET >> (12 - 3)) & ~(UInt32)7;
        BR_CONVERT_VAL(z, c)
        v &= 0x1f;
        v |= 0x90000000;
        v |= z << 26;
        v |= 0x00ffffe0 & ((z & (((flag << 1) - 1))) - flag);
        SetUi32a(p - 4, v)
      }
    }
  }
}
Z7_BRANCH_FUNCS_IMP(BranchConv_ARM64)


Z7_BRANCH_FUNC_MAIN(BranchConv_ARM)
{
  // Byte *p = data;
  const Byte *lim;
  size &= ~(SizeT)3;
  lim = p + size;
  BR_PC_INIT
  /* in ARM: branch offset is relative to the +2 instructions from current instruction.
     (p) will point to next instruction */
  pc += 8 - 4;

  for (;;)
  {
    for (;;)
    {
      if Z7_UNLIKELY(p >= lim) { return p; }  p += 4;  if Z7_UNLIKELY(p[-1] == 0xeb) break;
      if Z7_UNLIKELY(p >= lim) { return p; }  p += 4;  if Z7_UNLIKELY(p[-1] == 0xeb) break;
    }
    {
      UInt32 v = GetUi32a(p - 4);
      UInt32 c = BR_PC_GET >> 2;
      BR_CONVERT_VAL(v, c)
      v &= 0x00ffffff;
      v |= 0xeb000000;
      SetUi32a(p - 4, v)
    }
  }
}
Z7_BRANCH_FUNCS_IMP(BranchConv_ARM)


Z7_BRANCH_FUNC_MAIN(BranchConv_PPC)
{
  // Byte *p = data;
  const Byte *lim;
  size &= ~(SizeT)3;
  lim = p + size;
  BR_PC_INIT
  pc -= 4;  // because (p) will point to next instruction

  for (;;)
  {
    UInt32 v;
    for (;;)
    {
      if Z7_UNLIKELY(p == lim)
        return p;
      // v = GetBe32a(p);
      v = *(UInt32 *)(void *)p;
      p += 4;
      // if ((v & 0xfc000003) == 0x48000001) break;
      // if ((p[-4] & 0xFC) == 0x48 && (p[-1] & 3) == 1) break;
      if Z7_UNLIKELY(
          ((v - Z7_CONV_BE_TO_NATIVE_CONST32(0x48000001))
              & Z7_CONV_BE_TO_NATIVE_CONST32(0xfc000003)) == 0) break;
    }
    {
      v = Z7_CONV_NATIVE_TO_BE_32(v);
      {
        UInt32 c = BR_PC_GET;
        BR_CONVERT_VAL(v, c)
      }
      v &= 0x03ffffff;
      v |= 0x48000000;
      SetBe32a(p - 4, v)
    }
  }
}
Z7_BRANCH_FUNCS_IMP(BranchConv_PPC)


#ifdef Z7_CPU_FAST_ROTATE_SUPPORTED
#define BR_SPARC_USE_ROTATE
#endif

Z7_BRANCH_FUNC_MAIN(BranchConv_SPARC)
{
  // Byte *p = data;
  const Byte *lim;
  const UInt32 flag = (UInt32)1 << 22;
  size &= ~(SizeT)3;
  lim = p + size;
  BR_PC_INIT
  pc -= 4;  // because (p) will point to next instruction
  for (;;)
  {
    UInt32 v;
    for (;;)
    {
      if Z7_UNLIKELY(p == lim)
        return p;
      /* // the code without GetBe32a():
      { const UInt32 v = GetUi16a(p) & 0xc0ff; p += 4; if (v == 0x40 || v == 0xc07f) break; }
      */
      v = GetBe32a(p);
      p += 4;
    #ifdef BR_SPARC_USE_ROTATE
      v = rotlFixed(v, 2);
      v += (flag << 2) - 1;
      if Z7_UNLIKELY((v & (3 - (flag << 3))) == 0)
    #else
      v += (UInt32)5 << 29;
      v ^= (UInt32)7 << 29;
      v += flag;
      if Z7_UNLIKELY((v & (0 - (flag << 1))) == 0)
    #endif
        break;
    }
    {
      // UInt32 v = GetBe32a(p - 4);
    #ifndef BR_SPARC_USE_ROTATE
      v <<= 2;
    #endif
      {
        UInt32 c = BR_PC_GET;
        BR_CONVERT_VAL(v, c)
      }
      v &= (flag << 3) - 1;
    #ifdef BR_SPARC_USE_ROTATE
      v -= (flag << 2) - 1;
      v = rotrFixed(v, 2);
    #else
      v -= (flag << 2);
      v >>= 2;
      v |= (UInt32)1 << 30;
    #endif
      SetBe32a(p - 4, v)
    }
  }
}
Z7_BRANCH_FUNCS_IMP(BranchConv_SPARC)


Z7_BRANCH_FUNC_MAIN(BranchConv_ARMT)
{
  // Byte *p = data;
  Byte *lim;
  size &= ~(SizeT)1;
  // if (size == 0) return p;
  if (size <= 2) return p;
  size -= 2;
  lim = p + size;
  BR_PC_INIT
  /* in ARM: branch offset is relative to the +2 instructions from current instruction.
     (p) will point to the +2 instructions from current instruction */
  // pc += 4 - 4;
  // if (encoding) pc -= 0xf800 << 1; else pc += 0xf800 << 1;
  // #define ARMT_TAIL_PROC { goto armt_tail; }
  #define ARMT_TAIL_PROC { return p; }

  do
  {
    /* in MSVC 32-bit x86 compilers:
       UInt32 version : it loads value from memory with movzx
       Byte   version : it loads value to 8-bit register (AL/CL)
       movzx version is slightly faster in some cpus
    */
    unsigned b1;
    // Byte / unsigned
    b1 = p[1];
    // optimized version to reduce one (p >= lim) check:
    // unsigned a1 = p[1];  b1 = p[3];  p += 2;  if Z7_LIKELY((b1 & (a1 ^ 8)) < 0xf8)
    for (;;)
    {
      unsigned b3; // Byte / UInt32
      /* (Byte)(b3) normalization can use low byte computations in MSVC.
         It gives smaller code, and no loss of speed in some compilers/cpus.
         But new MSVC 32-bit x86 compilers use more slow load
         from memory to low byte register in that case.
         So we try to use full 32-bit computations for faster code.
      */
      // if (p >= lim) { ARMT_TAIL_PROC }  b3 = b1 + 8;  b1 = p[3];  p += 2;  if ((b3 & b1) >= 0xf8) break;
      if Z7_UNLIKELY(p >= lim) { ARMT_TAIL_PROC }  b3 = p[3];  p += 2;  if Z7_UNLIKELY((b3 & (b1 ^ 8)) >= 0xf8) break;
      if Z7_UNLIKELY(p >= lim) { ARMT_TAIL_PROC }  b1 = p[3];  p += 2;  if Z7_UNLIKELY((b1 & (b3 ^ 8)) >= 0xf8) break;
    }
    {
      /* we can adjust pc for (0xf800) to rid of (& 0x7FF) operation.
         But gcc/clang for arm64 can use bfi instruction for full code here */
      UInt32 v =
          ((UInt32)GetUi16a(p - 2) << 11) |
          ((UInt32)GetUi16a(p) & 0x7FF);
      /*
      UInt32 v =
            ((UInt32)p[1 - 2] << 19)
          + (((UInt32)p[1] & 0x7) << 8)
          + (((UInt32)p[-2] << 11))
          + (p[0]);
      */
      p += 2;
      {
        UInt32 c = BR_PC_GET >> 1;
        BR_CONVERT_VAL(v, c)
      }
      SetUi16a(p - 4, (UInt16)(((v >> 11) & 0x7ff) | 0xf000))
      SetUi16a(p - 2, (UInt16)(v | 0xf800))
      /*
      p[-4] = (Byte)(v >> 11);
      p[-3] = (Byte)(0xf0 | ((v >> 19) & 0x7));
      p[-2] = (Byte)v;
      p[-1] = (Byte)(0xf8 | (v >> 8));
      */
    }
  }
  while (p < lim);
  return p;
  // armt_tail:
  // if ((Byte)((lim[1] & 0xf8)) != 0xf0) { lim += 2; }  return lim;
  // return (Byte *)(lim + ((Byte)((lim[1] ^ 0xf0) & 0xf8) == 0 ? 0 : 2));
  // return (Byte *)(lim + (((lim[1] ^ ~0xfu) & ~7u) == 0 ? 0 : 2));
  // return (Byte *)(lim + 2 - (((((unsigned)lim[1] ^ 8) + 8) >> 7) & 2));
}
Z7_BRANCH_FUNCS_IMP(BranchConv_ARMT)


// #define BR_IA64_NO_INLINE

Z7_BRANCH_FUNC_MAIN(BranchConv_IA64)
{
  // Byte *p = data;
  const Byte *lim;
  size &= ~(SizeT)15;
  lim = p + size;
  pc -= 1 << 4;
  pc >>= 4 - 1;
  // pc -= 1 << 1;

  for (;;)
  {
    unsigned m;
    for (;;)
    {
      if Z7_UNLIKELY(p == lim)
        return p;
      m = (unsigned)((UInt32)0x334b0000 >> (*p & 0x1e));
      p += 16;
      pc += 1 << 1;
      if (m &= 3)
        break;
    }
    {
      p += (ptrdiff_t)m * 5 - 20; // negative value is expected here.
      do
      {
        const UInt32 t =
          #if defined(MY_CPU_X86_OR_AMD64)
            // we use 32-bit load here to reduce code size on x86:
            GetUi32(p);
          #else
            GetUi16(p);
          #endif
        UInt32 z = GetUi32(p + 1) >> m;
        p += 5;
        if (((t >> m) & (0x70 << 1)) == 0
            && ((z - (0x5000000 << 1)) & (0xf000000 << 1)) == 0)
        {
          UInt32 v = (UInt32)((0x8fffff << 1) | 1) & z;
          z ^= v;
        #ifdef BR_IA64_NO_INLINE
          v |= (v & ((UInt32)1 << (23 + 1))) >> 3;
          {
            UInt32 c = pc;
            BR_CONVERT_VAL(v, c)
          }
          v &= (0x1fffff << 1) | 1;
        #else
          {
            if (encoding)
            {
              // pc &= ~(0xc00000 << 1); // we just need to clear at least 2 bits
              pc &= (0x1fffff << 1) | 1;
              v += pc;
            }
            else
            {
              // pc |= 0xc00000 << 1; // we need to set at least 2 bits
              pc |= ~(UInt32)((0x1fffff << 1) | 1);
              v -= pc;
            }
          }
          v &= ~(UInt32)(0x600000 << 1);
        #endif
          v += (0x700000 << 1);
          v &= (0x8fffff << 1) | 1;
          z |= v;
          z <<= m;
          SetUi32(p + 1 - 5, z)
        }
        m++;
      }
      while (m &= 3); // while (m < 4);
    }
  }
}
Z7_BRANCH_FUNCS_IMP(BranchConv_IA64)


#define BR_CONVERT_VAL_ENC(v)  v += BR_PC_GET;
#define BR_CONVERT_VAL_DEC(v)  v -= BR_PC_GET;

#if 1 && defined(MY_CPU_LE_UNALIGN)
  #define RISCV_USE_UNALIGNED_LOAD
#endif

#ifdef RISCV_USE_UNALIGNED_LOAD
  #define RISCV_GET_UI32(p)      GetUi32(p)
  #define RISCV_SET_UI32(p, v)   { SetUi32(p, v) }
#else
  #define RISCV_GET_UI32(p) \
    ((UInt32)GetUi16a(p) + \
    ((UInt32)GetUi16a((p) + 2) << 16))
  #define RISCV_SET_UI32(p, v) { \
    SetUi16a(p, (UInt16)(v)) \
    SetUi16a((p) + 2, (UInt16)(v >> 16)) }
#endif

#if 1 && defined(MY_CPU_LE)
  #define RISCV_USE_16BIT_LOAD
#endif

#ifdef RISCV_USE_16BIT_LOAD
  #define RISCV_LOAD_VAL(p)  GetUi16a(p)
#else
  #define RISCV_LOAD_VAL(p)  (*(p))
#endif

#define RISCV_INSTR_SIZE  2
#define RISCV_STEP_1      (4 + RISCV_INSTR_SIZE)
#define RISCV_STEP_2      4
#define RISCV_REG_VAL     (2 << 7)
#define RISCV_CMD_VAL     3
#if 1
  // for code size optimization:
  #define RISCV_DELTA_7F  0x7f
#else
  #define RISCV_DELTA_7F  0
#endif

#define RISCV_CHECK_1(v, b) \
    (((((b) - RISCV_CMD_VAL) ^ ((v) << 8)) & (0xf8000 + RISCV_CMD_VAL)) == 0)

#if 1
  #define RISCV_CHECK_2(v, r) \
    ((((v) - ((RISCV_CMD_VAL << 12) | RISCV_REG_VAL | 8)) \
           << 18) \
     < ((r) & 0x1d))
#else
  // this branch gives larger code, because
  // compilers generate larger code for big constants.
  #define RISCV_CHECK_2(v, r) \
    ((((v) - ((RISCV_CMD_VAL << 12) | RISCV_REG_VAL)) \
           & ((RISCV_CMD_VAL << 12) | RISCV_REG_VAL)) \
     < ((r) & 0x1d))
#endif


#define RISCV_SCAN_LOOP \
  Byte *lim; \
  size &= ~(SizeT)(RISCV_INSTR_SIZE - 1); \
  if (size <= 6) return p; \
  size -= 6; \
  lim = p + size; \
  BR_PC_INIT \
  for (;;) \
  { \
    UInt32 a, v; \
    /* Z7_PRAGMA_OPT_DISABLE_LOOP_UNROLL_VECTORIZE */ \
    for (;;) \
    { \
      if Z7_UNLIKELY(p >= lim) { return p; } \
      a = (RISCV_LOAD_VAL(p) ^ 0x10u) + 1; \
      if ((a & 0x77) == 0) break; \
      a = (RISCV_LOAD_VAL(p + RISCV_INSTR_SIZE) ^ 0x10u) + 1; \
      p += RISCV_INSTR_SIZE * 2; \
      if ((a & 0x77) == 0) \
      { \
        p -= RISCV_INSTR_SIZE; \
        if Z7_UNLIKELY(p >= lim) { return p; } \
        break; \
      } \
    }
// (xx6f ^ 10) + 1 = xx7f + 1 = xx80       : JAL
// (xxef ^ 10) + 1 = xxff + 1 = xx00 + 100 : JAL
// (xx17 ^ 10) + 1 = xx07 + 1 = xx08       : AUIPC
// (xx97 ^ 10) + 1 = xx87 + 1 = xx88       : AUIPC

Byte * Z7_BRANCH_CONV_ENC(RISCV)(Byte *p, SizeT size, UInt32 pc)
{
  RISCV_SCAN_LOOP
    v = a;
    a = RISCV_GET_UI32(p);
#ifndef RISCV_USE_16BIT_LOAD
    v += (UInt32)p[1] << 8;
#endif

    if ((v & 8) == 0) // JAL
    {
      if ((v - (0x100 /* - RISCV_DELTA_7F */)) & 0xd80)
      {
        p += RISCV_INSTR_SIZE;
        continue;
      }
      {
        v = ((a &    1u << 31) >> 11)
          | ((a & 0x3ff << 21) >> 20)
          | ((a &     1 << 20) >> 9)
          |  (a &  0xff << 12);
        BR_CONVERT_VAL_ENC(v)
        // ((v & 1) == 0)
        // v: bits [1 : 20] contain offset bits
#if 0 && defined(RISCV_USE_UNALIGNED_LOAD)
        a &= 0xfff;
        a |= ((UInt32)(v << 23))
          |  ((UInt32)(v <<  7) & ((UInt32)0xff << 16))
          |  ((UInt32)(v >>  5) & ((UInt32)0xf0 << 8));
        RISCV_SET_UI32(p, a)
#else // aligned
#if 0
        SetUi16a(p, (UInt16)(((v >> 5) & 0xf000) | (a & 0xfff)))
#else
        p[1] = (Byte)(((v >> 13) & 0xf0) | ((a >> 8) & 0xf));
#endif

#if 1 && defined(Z7_CPU_FAST_BSWAP_SUPPORTED) && defined(MY_CPU_LE)
        v <<= 15;
        v = Z7_BSWAP32(v);
        SetUi16a(p + 2, (UInt16)v)
#else
        p[2] = (Byte)(v >> 9);
        p[3] = (Byte)(v >> 1);
#endif
#endif // aligned
      }
      p += 4;
      continue;
    } // JAL

    {
      // AUIPC
      if (v & 0xe80)  // (not x0) and (not x2)
      {
        const UInt32 b = RISCV_GET_UI32(p + 4);
        if (RISCV_CHECK_1(v, b))
        {
          {
            const UInt32 temp = (b << 12) | (0x17 + RISCV_REG_VAL);
            RISCV_SET_UI32(p, temp)
          }
          a &= 0xfffff000;
          {
#if 1
          const int t = -1 >> 1;
          if (t != -1)
            a += (b >> 20) - ((b >> 19) & 0x1000); // arithmetic right shift emulation
          else
#endif
            a += (UInt32)((Int32)b >> 20); // arithmetic right shift (sign-extension).
          }
          BR_CONVERT_VAL_ENC(a)
#if 1 && defined(Z7_CPU_FAST_BSWAP_SUPPORTED) && defined(MY_CPU_LE)
          a = Z7_BSWAP32(a);
          RISCV_SET_UI32(p + 4, a)
#else
          SetBe32(p + 4, a)
#endif
          p += 8;
        }
        else
          p += RISCV_STEP_1;
      }
      else
      {
        UInt32 r = a >> 27;
        if (RISCV_CHECK_2(v, r))
        {
          v = RISCV_GET_UI32(p + 4);
          r = (r << 7) + 0x17 + (v & 0xfffff000);
          a = (a >> 12) | (v << 20);
          RISCV_SET_UI32(p, r)
          RISCV_SET_UI32(p + 4, a)
          p += 8;
        }
        else
          p += RISCV_STEP_2;
      }
    }
  } // for
}


Byte * Z7_BRANCH_CONV_DEC(RISCV)(Byte *p, SizeT size, UInt32 pc)
{
  RISCV_SCAN_LOOP
#ifdef RISCV_USE_16BIT_LOAD
    if ((a & 8) == 0)
    {
#else
    v = a;
    a += (UInt32)p[1] << 8;
    if ((v & 8) == 0)
    {
#endif
      // JAL
      a -= 0x100 - RISCV_DELTA_7F;
      if (a & 0xd80)
      {
        p += RISCV_INSTR_SIZE;
        continue;
      }
      {
        const UInt32 a_old = (a + (0xef - RISCV_DELTA_7F)) & 0xfff;
#if 0 // unaligned
        a = GetUi32(p);
        v = (UInt32)(a >> 23) & ((UInt32)0xff << 1)
          | (UInt32)(a >>  7) & ((UInt32)0xff << 9)
#elif 1 && defined(Z7_CPU_FAST_BSWAP_SUPPORTED) && defined(MY_CPU_LE)
        v = GetUi16a(p + 2);
        v = Z7_BSWAP32(v) >> 15
#else
        v = (UInt32)p[3] << 1
          | (UInt32)p[2] << 9
#endif
          | (UInt32)((a & 0xf000) << 5);
        BR_CONVERT_VAL_DEC(v)
        a = a_old
          | (v << 11 &    1u << 31)
          | (v << 20 & 0x3ff << 21)
          | (v <<  9 &     1 << 20)
          | (v       &  0xff << 12);
        RISCV_SET_UI32(p, a)
      }
      p += 4;
      continue;
    } // JAL

    {
      // AUIPC
      v = a;
#if 1 && defined(RISCV_USE_UNALIGNED_LOAD)
      a = GetUi32(p);
#else
      a |= (UInt32)GetUi16a(p + 2) << 16;
#endif
      if ((v & 0xe80) == 0)  // x0/x2
      {
        const UInt32 r = a >> 27;
        if (RISCV_CHECK_2(v, r))
        {
          UInt32 b;
#if 1 && defined(Z7_CPU_FAST_BSWAP_SUPPORTED) && defined(MY_CPU_LE)
          b = RISCV_GET_UI32(p + 4);
          b = Z7_BSWAP32(b);
#else
          b = GetBe32(p + 4);
#endif
          v = a >> 12;
          BR_CONVERT_VAL_DEC(b)
          a = (r << 7) + 0x17;
          a += (b + 0x800) & 0xfffff000;
          v |= b << 20;
          RISCV_SET_UI32(p, a)
          RISCV_SET_UI32(p + 4, v)
          p += 8;
        }
        else
          p += RISCV_STEP_2;
      }
      else
      {
        const UInt32 b = RISCV_GET_UI32(p + 4);
        if (!RISCV_CHECK_1(v, b))
          p += RISCV_STEP_1;
        else
        {
          v = (a & 0xfffff000) | (b >> 20);
          a = (b << 12) | (0x17 + RISCV_REG_VAL);
          RISCV_SET_UI32(p, a)
          RISCV_SET_UI32(p + 4, v)
          p += 8;
        }
      }
    }
  } // for
}