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duckstation/dep/lzma/src/Bra.c

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/* 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
}
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