Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
Is there any SSE instruction (up to version 4.2) that automatically fills four XMM registers with the value of the four words of another XMM register?
Example: running the instruction on the word ABCD would fill four XMM registers: AAAA, BBBB, CCCC, and DDDD.
I do not believe there is a single operation, but four
pshufdoperations (one for each destination) will do the job; see http://lists.apple.com/archives/perfoptimization-dev/2007/Feb/msg00002.html (the first code example, after themovdinstruction). There are similar variants ofpshufdto replicate the other parts of the register. I believe the constants to use in the instruction are 0, 85, 170, and 255 for the four parts of the register.