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Compiler-specific Features
4.7.51 __qadd8 intrinsic
This intrinsic inserts a QADD8 instruction into the instruction stream generated by the
compiler. It enables you to perform four 8-bit integer additions, saturating the results to
the 8-bit signed integer range -2 7 ≤ x ≤ 2 7 - 1.
unsigned int __qadd8(unsigned int val1, unsigned int val2)
Where:
val1
val2
holds the first four 8-bit summands
holds the other four 8-bit summands.
The __qadd8 intrinsic returns:
• the saturated addition of the first byte of each operand in the first byte of the return
value
• the saturated addition of the second byte of each operand in the second byte of the
return value
• the saturated addition of the third byte of each operand in the third byte of the
return value
• the saturated addition of the fourth byte of each operand in the fourth byte of the
return value.
The returned results are saturated to the 16-bit signed integer range -2 7 ≤ x ≤ 2 7 - 1.
Example:
unsigned int add_bytes(unsigned int val1, unsigned int val2)
{
unsigned int res;
}
res = __qadd8(val1,val2); /* res[7:0] = val1[7:0] + val2[7:0]
res[15:8] = val1[15:8] + val2[15:8]
res[23:16] = val1[23:16] + val2[23:16]
res[31:24] = val1[31:24] + val2[31:24]
*/
return res;
See also
• ARMv6 SIMD intrinsics on page 4-109
• Instruction summary on page 4-2 in the Assembler Guide
• Saturating instructions on page 4-93 in the Assembler Guide
• QADD, QSUB, QDADD, and QDSUB on page 4-94 in the Assembler Guide.
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