Assembler: jmpf, testb and else instructions

Help me 开发者_高级运维please, i don't understand this code:

...
BUFFER = 0x0600
...
rep movs jmpf BUFFER+migrate, 0 ;???
migrate:
findactive:
testb dl,dl ; ???
jns nextdisk

I'm an old x86 coder. I have to admit I don't understand your code either. The "movs" instruction line looks illegal. Are you sure you've transcribed the code correctly?

This is a part of the code from MasterBootRecord. After coping a sector from bootdrive to memory address 7C00h for IBM PC, need copy this code to new address(usualy on 0600h, first free memory), using "rep movs", and then continue safe execution but from new allocation "jmpf BUFFER+migrate,0"(jmpf offset, segment). Someone forgot push "Enter" after "rep movs".