3 ms·
Rep movsb copies 64K if CX=0 (that's actually very useful), but memcpy could be implemented as two instructions: jcxz skip rep movsb skip:
by bonzini 2y ago
Rep movsb copies 64K if CX=0 (that's actually very useful), but memcpy could be implemented as two instructions:
jcxz skip
rep movsb
skip: