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Compiler-specific Features
4.7.82 __sxtab16 intrinsic
This intrinsic inserts an SXTAB16 instruction into the instruction stream generated by the
compiler. It enables you to extract two 8-bit values from the second operand (at bit
positions [7:0] and [23:16]), sign-extend them to 16-bits each, and add the results to the
first operand.
unsigned int __sxtab16(unsigned int val1, unsigned int val2)
Where:
val1
val2
holds the values that the extracted and sign-extended values are added to
holds the two 8-bit values to be extracted and sign-extended.
The __sxtab16 intrinsic returns the addition of val1 and val2, where the 8-bit values in
val2[7:0] and val2[23:16] have been extracted and sign-extended prior to the addition.
Example:
unsigned int extract_sign_extend_and_add(unsigned int val1, unsigned int val2)
{
unsigned int res;
res = __sxtab16(val1,val2); /* res[15:0]
= val1[15:0] + SignExtended(val2[7:0])
}
return res;
res[31:16]
= val1[31:16] + SignExtended(val2[23:16])
*/
See also
• ARMv6 SIMD intrinsics on page 4-109
• Instruction summary on page 4-2 in the Assembler Guide
• SXT, SXTA, UXT, and UXTA on page 4-109 in the Assembler Guide.
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