| |||
| Home > ARMv6 SIMD Instruction Intrinsics > __sadd8 intrinsic | |||
This intrinsic inserts an SADD8 instruction into
the instruction stream generated by the compiler. It enables you
to perform four 8-bit signed integer additions. The GE bits in the
APSR are set according to the results of the additions.
unsigned int __sadd8(unsigned intval1, unsigned intval2)
Where:
val1holds the first four 8-bit summands
val2holds the second four 8-bit summands.
The __sadd8 intrinsic returns:
the addition of the first bytes from each operand, in the first byte of the return value
the addition of the second bytes of each operand, in the second byte of the return value
the addition of the third bytes of each operand, in the third byte of the return value
the addition of the fourth bytes of each operand, in the fourth byte of the return value.
Each bit in APSR.GE is set or cleared for each byte in the
return value, depending on the results of the operation. If is
the return value, then:res
if [7:0]
≥ 0 then APSR.GE[0] = 1 else 0res
if [15:8]
≥ 0 then APSR.GE[1] = 1 else 0.res
if [23:16]
≥ 0 then APSR.GE[2] = 1 else 0.res
if [31:24]
≥ 0 then APSR.GE[3] = 1 else 0.res
Example:
unsigned int add_bytes(unsigned int val1, unsigned int val2)
{
unsigned int res;
res = __sadd16(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;
}