From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Jacobowitz To: Andrew Cagney Cc: gdb-patches@sources.redhat.com Subject: Re: [RFA] Add mips_software_single_step Date: Thu, 05 Jul 2001 16:10:00 -0000 Message-id: <20010705161039.A15664@nevyn.them.org> References: <20010704115630.A16310@nevyn.them.org> <3B44E116.4070009@cygnus.com> <20010705150511.A27593@nevyn.them.org> <3B44EF32.8010009@cygnus.com> X-SW-Source: 2001-07/msg00126.html On Thu, Jul 05, 2001 at 06:50:26PM -0400, Andrew Cagney wrote: > > On Thu, Jul 05, 2001 at 05:50:14PM -0400, Andrew Cagney wrote: > > > >> > This function's pretty straightforward; the Linux port uses it. Ok to > >> > commit? > > > >> > >> > >> How does the linux port use it? As a tweek to the multi-arch vector or > >> as a macro/function? If the former then it should be static, if the > >> latter than a declaration in mips-tdep.h or tm-mips.h (?) is needed. > > > > > > As a macro: > > > > #define SOFTWARE_SINGLE_STEP_P() 1 > > extern void mips_software_single_step (unsigned int, int); > > #define SOFTWARE_SINGLE_STEP(sig,bp_p) mips_software_single_step (sig, bp_p) > > > The macro definition appearing in config/mips/tm-linux.h but the > function declaration appearing in config/mips/tm-mips.h? The function > declaration is in tm-mips.h so that mips-tdep.c always sees it. Right. My source right now has the declaration in tm-linux.h, but tm-mips.h is more appropriate; I'll move it before I commit. > > I'm sensing that this belongs in the multi-arch vector, though. I'll > > change that. > > > For the moment the above is ok. OK, then. Is the style-corrected version below OK? > We're getting into the relm of theory :-) No one has so far tried to do > this. (Well, ok I think Eli is setting himself up for the challenge on > IRIX.) I guess I'll revisit this along with Eli once I get the port settled in some basic state, then. -- Daniel Jacobowitz Carnegie Mellon University MontaVista Software Debian GNU/Linux Developer 2001-07-04 Daniel Jacobowitz * mips-tdep.c (mips_software_single_step): New function. * config/mips/tm-mips.h: Add prototype for mips_software_single_step. Index: config/mips/tm-mips.h =================================================================== RCS file: /cvs/src/src/gdb/config/mips/tm-mips.h,v retrieving revision 1.20 diff -u -r1.20 tm-mips.h --- tm-mips.h 2001/06/15 23:10:55 1.20 +++ tm-mips.h 2001/07/05 23:00:08 @@ -502,3 +502,6 @@ /* MIPS sign extends addresses */ #define POINTER_TO_ADDRESS(TYPE,BUF) (signed_pointer_to_address (TYPE, BUF)) #define ADDRESS_TO_POINTER(TYPE,BUF,ADDR) (address_to_signed_pointer (TYPE, BUF, ADDR)) + +/* Single step based on where the current instruction will take us. */ +extern void mips_software_single_step (enum target_signal, int); Index: mips-tdep.c =================================================================== RCS file: /cvs/src/src/gdb/mips-tdep.c,v retrieving revision 1.54 diff -u -r1.54 mips-tdep.c --- mips-tdep.c 2001/06/16 20:00:24 1.54 +++ mips-tdep.c 2001/07/05 23:00:09 @@ -1379,6 +1392,33 @@ return addr; } +/* mips_software_single_step() is called just before we want to resume + the inferior, if we want to single-step it but there is no hardware + or kernel single-step support (MIPS on Linux for example). We find + the target of the coming instruction and breakpoint it. + + single_step is also called just after the inferior stops. If we had + set up a simulated single-step, we undo our damage. */ + +void +mips_software_single_step (enum target_signal sig, int insert_breakpoints_p) +{ + static CORE_ADDR next_pc; + typedef char binsn_quantum[BREAKPOINT_MAX]; + static binsn_quantum break_mem; + CORE_ADDR pc; + + if (insert_breakpoints_p) + { + pc = read_register (PC_REGNUM); + next_pc = mips_next_pc (pc); + + target_insert_breakpoint (next_pc, break_mem); + } + else + target_remove_breakpoint (next_pc, break_mem); +} + static void mips_init_frame_pc_first (int fromleaf, struct frame_info *prev) {