Hi Andreas,
On 27/07/20 9:08 AM, Andreas Schwab wrote:
On Jul 27 2020, Michael Schmitz wrote:
Hi Andreas,
On 26/07/20 11:03 PM, Andreas Schwab wrote:
On Jul 26 2020, Michael Schmitz wrote:
No particular reason - I had seen testb used in the syscall entry code and
Where? That may be bugs.
Here:
ENTRY(ret_from_signal)
movel %curptr@(TASK_STACK),%a1
tstb %a1@(TINFO_FLAGS+2)
jge 1f
jbsr syscall_trace_leave
1: RESTORE_SWITCH_STACK
addql #4,%sp
....
and here:
ENTRY(system_call)
SAVE_ALL_SYS
GET_CURRENT(%d1)
movel %d1,%a1
| save top of frame
movel %sp,%curptr@(TASK_THREAD+THREAD_ESP0)
| syscall trace?
tstb %a1@(TINFO_FLAGS+2)
jmi do_trace_entry
cmpl #NR_syscalls,%d0
jcc badsys
How is that relevant? That is testing a single bit, of course.
No, tstb tests a byte operand. btst tests a bit. And testing the second
byte of the thread info flags is just what we need if the trace bits are
14 and 15.
(Had to look up the m68k programmer's reference and check to be sure,
admittedly.)
Cheers,
Michael
Andreas.
