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Source code

AESDECWIDE128KL

Perform Ten Rounds of AES Decryption Flow With Key Locker on 8 Blocks

stableVMJITAOTinstruction

Encodings

OpcodeInstructionOp/En64-bitCompat/LegacyDescription
F3 0F 38 D8 !(11):001:bbbAESDECWIDE128KL m384, <XMM0-7>AValidValidDecrypt XMM0-7 using 128-bit AES key indicated by handle at m384 and store each resultant block back to its corresponding register.

Operand encoding

Each mode is a value of the Op/En column above. It says which field of the encoded instruction carries each operand, in the order they are written, and whether the instruction reads it, writes it or both.

A

  1. modrm.rm lecturaModRM byte, r/m field (bits 2-0); with the SIB byte and the displacement when the mod field asks for them
  2. XMM0-7 lectura y escritura

Measured cost

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Flags named

Description

The AESDECWIDE128KL1 instruction performs ten rounds of AES to decrypt each of the eight blocks in XMM0-7 using the 128-bit key indicated by the handle from the second operand. It replaces each input block in XMM0-7 with its corresponding decrypted block if the operation succeeds (e.g., does not run into a handle violation failure).

Operation

AESDECWIDE128KL
Handle := UnalignedLoad of 384 bit (SRC); // Load is not guaranteed to be atomic.
Illegal Handle = (HandleReservedBitSet (Handle) ||

                   (Handle[0] AND (CPL > 0)) ||
                   Handle [2] ||
                   HandleKeyType (Handle) != HANDLE_KEY_TYPE_AES128);
IF (Illegal Handle)
    THEN RFLAGS.ZF := 1;
    ELSE
          (UnwrappedKey, Authentic) := UnwrapKeyAndAuthenticate384 (Handle[383:0], IWKey);
          IF Authentic == 0 {
                THEN RFLAGS.ZF := 1;
                ELSE

                      XMM0 := AES128Decrypt (XMM0, UnwrappedKey) ;
                      XMM1 := AES128Decrypt (XMM1, UnwrappedKey) ;
                      XMM2 := AES128Decrypt (XMM2, UnwrappedKey) ;
                      XMM3 := AES128Decrypt (XMM3, UnwrappedKey) ;
                      XMM4 := AES128Decrypt (XMM4, UnwrappedKey) ;
                      XMM5 := AES128Decrypt (XMM5, UnwrappedKey) ;
                      XMM6 := AES128Decrypt (XMM6, UnwrappedKey) ;
                      XMM7 := AES128Decrypt (XMM7, UnwrappedKey) ;
                      RFLAGS.ZF := 0;
          FI;
FI;
RFLAGS.OF, SF, AF, PF, CF := 0;

Flags affected

ZF is set to 0 if the operation succeeded and set to 1 if the operation failed due to a handle violation. The other arithmetic flags (OF, SF, AF, PF, CF) are cleared to 0.

  1. Further details on Key Locker and usage of this instruction can be found here: https://software.intel.com/content/www/us/en/develop/download/intel-key-locker-specification.html.

Intel C/C++ compiler intrinsics

AESDECWIDE128KLunsigned char _mm_aesdecwide128kl_u8(__m128i odata[8], const __m128i idata[8], const void* h);

Exceptions

Real address mode
#UDIf the LOCK prefix is used. If CPUID.07H.00H:ECX.KEY_LOCKER[23] = 0. If CR4.KL = 0. If CPUID.19H:EBX.AESKLE[0] = 0. If CR0.EM = 1. If CR4.OSFXSR = 0. If CPUID.19H:EBX.AES_WIDE[2] = 0.
#NMIf CR0.TS = 1.
#PFIf a page fault occurs.
#GP(0)If a memory operand effective address is outside the CS, DS, ES, FS, or GS segment limit. If the DS, ES, FS, or GS register is used to access memory and it contains a NULL segment selector. If the memory address is in a non-canonical form.
#SS(0)If a memory operand effective address is outside the SS segment limit. If a memory address referencing the SS segment is in a non-canonical form.
Protected mode
#UDIf the LOCK prefix is used. If CPUID.07H.00H:ECX.KEY_LOCKER[23] = 0. If CR4.KL = 0. If CPUID.19H:EBX.AESKLE[0] = 0. If CR0.EM = 1. If CR4.OSFXSR = 0. If CPUID.19H:EBX.AES_WIDE[2] = 0.
#NMIf CR0.TS = 1.
#PFIf a page fault occurs.
#GP(0)If a memory operand effective address is outside the CS, DS, ES, FS, or GS segment limit. If the DS, ES, FS, or GS register is used to access memory and it contains a NULL segment selector. If the memory address is in a non-canonical form.
#SS(0)If a memory operand effective address is outside the SS segment limit. If a memory address referencing the SS segment is in a non-canonical form.
Virtual-8086 mode
#UDIf the LOCK prefix is used. If CPUID.07H.00H:ECX.KEY_LOCKER[23] = 0. If CR4.KL = 0. If CPUID.19H:EBX.AESKLE[0] = 0. If CR0.EM = 1. If CR4.OSFXSR = 0. If CPUID.19H:EBX.AES_WIDE[2] = 0.
#NMIf CR0.TS = 1.
#PFIf a page fault occurs.
#GP(0)If a memory operand effective address is outside the CS, DS, ES, FS, or GS segment limit. If the DS, ES, FS, or GS register is used to access memory and it contains a NULL segment selector. If the memory address is in a non-canonical form.
#SS(0)If a memory operand effective address is outside the SS segment limit. If a memory address referencing the SS segment is in a non-canonical form.
Compatibility mode
#UDIf the LOCK prefix is used. If CPUID.07H.00H:ECX.KEY_LOCKER[23] = 0. If CR4.KL = 0. If CPUID.19H:EBX.AESKLE[0] = 0. If CR0.EM = 1. If CR4.OSFXSR = 0. If CPUID.19H:EBX.AES_WIDE[2] = 0.
#NMIf CR0.TS = 1.
#PFIf a page fault occurs.
#GP(0)If a memory operand effective address is outside the CS, DS, ES, FS, or GS segment limit. If the DS, ES, FS, or GS register is used to access memory and it contains a NULL segment selector. If the memory address is in a non-canonical form.
#SS(0)If a memory operand effective address is outside the SS segment limit. If a memory address referencing the SS segment is in a non-canonical form.
64-bit mode
#UDIf the LOCK prefix is used. If CPUID.07H.00H:ECX.KEY_LOCKER[23] = 0. If CR4.KL = 0. If CPUID.19H:EBX.AESKLE[0] = 0. If CR0.EM = 1. If CR4.OSFXSR = 0. If CPUID.19H:EBX.AES_WIDE[2] = 0.
#NMIf CR0.TS = 1.
#PFIf a page fault occurs.
#GP(0)If a memory operand effective address is outside the CS, DS, ES, FS, or GS segment limit. If the DS, ES, FS, or GS register is used to access memory and it contains a NULL segment selector. If the memory address is in a non-canonical form.
#SS(0)If a memory operand effective address is outside the SS segment limit. If a memory address referencing the SS segment is in a non-canonical form.

Sources