问题
How do you print FPU registers using lldb?
In gdb, you would do something like p $st0, however doing the same in lldb results in the error: error: use of undeclared identifier '$st0'.
register read st0 doesn't work either and gives the error error: Invalid register name 'st0'..
回答1:
By using register read --all as suggested by paulsm4, I found that the name of the registers are actually stmm0 to stmm7 and not st0 to st7.
So doing register read stmm0 --format b will get you the binary representation of the float.
来源：https://stackoverflow.com/questions/14093585/print-fpu-registers-in-lldb