adox
Unsigned Integer Addition of Two Operands with Overflow Flag
Adds with Overflow Flag (Parallel addition with ADCX).
Pseudocode Operation
temp ← dest + src + OF;
OF ← (signed_overflow(dest, src, temp)) ? 1 : 0;
dest ← temp & 0xFFFFFFFF;Example
Encoding
Operands
-
dest
32-bit general-purpose register (e.g. EAX) -
src
32-bit register or memory
Related
More in ADX
Reference
Instruction Forms
| Opcode | Instruction | Op/En | 64/32-bit Mode | CPUID | Description |
|---|---|---|---|---|---|
| F3 0F 38 F6 /r | ADOX r32, r/m32 | RM | V/V | ADX RM ADX | Unsigned addition of r32 with OF, r/m32 to r32, writes OF. F3 REX.w 0F 38 F6 /r V/N.E. Unsigned addition of r64 with OF, r/m64 to r64, writes OF. ADOX r64, r/m64 |
Description
Performs an unsigned addition of the destination operand (first operand), the source operand (second operand) and the overflow-flag (OF) and stores the result in the destination operand. The destination operand is a generalpurpose register, whereas the source operand can be a general-purpose register or memory location. The state of OF represents a carry from a previous addition. The instruction sets the OF flag with the carry generated by the unsigned addition of the operands. The ADOX instruction is executed in the context of multi-precision addition, where we add a series of operands with a carry-chain. At the beginning of a chain of additions, we execute an instruction to zero the OF (e.g. XOR). This instruction is supported in real mode and virtual-8086 mode. The operand size is always 32 bits if not in 64bit mode. In 64-bit mode, the default operation size is 32 bits. Using a REX Prefix in the form of REX.R permits access to additional registers (R8-15). Using REX Prefix in the form of REX.W promotes operation to 64-bits. ADOX executes normally either inside or outside a transaction region. Note: ADOX defines the CF and OF flags differently than the ADD/ADC instructions as defined in Intel® 64 and IA-32 Architectures Software Developer’s Manual, Volume 2A.
Operation
IF OperandSize is 64-bit THEN OF:DEST[63:0] := DEST[63:0] + SRC[63:0] + OF; ELSE OF:DEST[31:0] := DEST[31:0] + SRC[31:0] + OF; FI;
Intel C/C++ Compiler Intrinsic Equivalent
unsigned char _addcarryx_u32 (unsigned char c_in, unsigned int src1, unsigned int src2, unsigned int *sum_out); unsigned char _addcarryx_u64 (unsigned char c_in, unsigned __int64 src1, unsigned __int64 src2, unsigned __int64 *sum_out);