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diff --git a/gdb/Convex.notes b/gdb/Convex.notes deleted file mode 100644 index 28d336b..0000000 --- a/gdb/Convex.notes +++ /dev/null @@ -1,163 +0,0 @@ - -@node Convex,,, Top -@appendix Convex-specific info -@cindex Convex notes - -Scalar registers are 64 bits long, which is a pain since -left half of an S register frequently contains noise. -Therefore there are two ways to obtain the value of an S register. - -@table @kbd -@item $s0 -returns the low half of the register as an int - -@item $S0 -returns the whole register as a long long -@end table - -You can print the value in floating point by using @samp{p/f $s0} or @samp{p/f $S0} -to print a single or double precision value. - -@cindex vector registers -Vector registers are handled similarly, with @samp{$V0} denoting the whole -64-bit register and @kbd{$v0} denoting the 32-bit low half; @samp{p/f $v0} -or @samp{p/f $V0} can be used to examine the register in floating point. -The length of the vector registers is taken from @samp{$vl}. - -Individual elements of a vector register are denoted in the obvious way; -@samp{print $v3[9]} prints the tenth element of register @kbd{v3}, and -@samp{set $v3[9] = 1234} alters it. - -@kbd{$vl} and @kbd{$vs} are int, and @kbd{$vm} is an int vector. -Elements of @kbd{$vm} can't be assigned to. - -@cindex communication registers -@kindex info comm-registers -Communication registers have names @kbd{$C0 .. $C63}, with @kbd{$c0 .. $c63} -denoting the low-order halves. @samp{info comm-registers} will print them -all out, and tell which are locked. (A communication register is -locked when a value is sent to it, and unlocked when the value is -received.) Communication registers are, of course, global to all -threads, so it does not matter what the currently selected thread is. -@samp{info comm-reg @var{name}} prints just that one communication -register; @samp{name} may also be a communication register number -@samp{nn} or @samp{0xnn}. -@samp{info comm-reg @var{address}} prints the contents of the resource -structure at that address. - -@kindex info psw -The command @samp{info psw} prints the processor status word @kbd{$ps} -bit by bit. - -@kindex set base -GDB normally prints all integers in base 10, but the leading -@kbd{0x80000000} of pointers is intolerable in decimal, so the default -output radix has been changed to try to print addresses appropriately. -The @samp{set base} command can be used to change this. - -@table @code -@item set base 10 -Integer values always print in decimal. - -@item set base 16 -Integer values always print in hex. - -@item set base -Go back to the initial state, which prints integer values in hex if they -look like pointers (specifically, if they start with 0x8 or 0xf in the -stack), otherwise in decimal. -@end table - -@kindex set pipeline -When an exception such as a bus error or overflow happens, usually the PC -is several instructions ahead by the time the exception is detected. -The @samp{set pipe} command will disable this. - -@table @code -@item set pipeline off -Forces serial execution of instructions; no vector chaining and no -scalar instruction overlap. With this, exceptions are detected with -the PC pointing to the instruction after the one in error. - -@item set pipeline on -Returns to normal, fast, execution. This is the default. -@end table - -@cindex parallel -In a parallel program, multiple threads may be executing, each -with its own registers, stack, and local memory. When one of them -hits a breakpoint, that thread is selected. Other threads do -not run while the thread is in the breakpoint. - -@kindex 1cont -The selected thread can be single-stepped, given signals, and so -on. Any other threads remain stopped. When a @samp{cont} command is given, -all threads are resumed. To resume just the selected thread, use -the command @samp{1cont}. - -@kindex thread -The @samp{thread} command will show the active threads and the -instruction they are about to execute. The selected thread is marked -with an asterisk. The command @samp{thread @var{n}} will select thread @var{n}, -shifting the debugger's attention to it for single-stepping, -registers, local memory, and so on. - -@kindex info threads -The @samp{info threads} command will show what threads, if any, have -invisibly hit breakpoints or signals and are waiting to be noticed. - -@kindex set parallel -The @samp{set parallel} command controls how many threads can be active. - -@table @code -@item set parallel off -One thread. Requests by the program that other threads join in -(spawn and pfork instructions) do not cause other threads to start up. -This does the same thing as the @samp{limit concurrency 1} command. - -@item set parallel fixed -All CPUs are assigned to your program whenever it runs. When it -executes a pfork or spawn instruction, it begins parallel execution -immediately. This does the same thing as the @samp{mpa -f} command. - -@item set parallel on -One or more threads. Spawn and pfork cause CPUs to join in when and if -they are free. This is the default. It is very good for system -throughput, but not very good for finding bugs in parallel code. If you -suspect a bug in parallel code, you probably want @samp{set parallel fixed.} -@end table - -@subsection Limitations - -WARNING: Convex GDB evaluates expressions in long long, because S -registers are 64 bits long. However, GDB expression semantics are not -exactly C semantics. This is a bug, strictly speaking, but it's not one I -know how to fix. If @samp{x} is a program variable of type int, then it -is also type int to GDB, but @samp{x + 1} is long long, as is @samp{x + y} -or any other expression requiring computation. So is the expression -@samp{1}, or any other constant. You only really have to watch out for -calls. The innocuous expression @samp{list_node (0x80001234)} has an -argument of type long long. You must explicitly cast it to int. - -It is not possible to continue after an uncaught fatal signal by using -@samp{signal 0}, @samp{return}, @samp{jump}, or anything else. The difficulty is with -Unix, not GDB. - -I have made no big effort to make such things as single-stepping a -@kbd{join} instruction do something reasonable. If the program seems to -hang when doing this, type @kbd{ctrl-c} and @samp{cont}, or use -@samp{thread} to shift to a live thread. Single-stepping a @kbd{spawn} -instruction apparently causes new threads to be born with their T bit set; -this is not handled gracefully. When a thread has hit a breakpoint, other -threads may have invisibly hit the breakpoint in the background; if you -clear the breakpoint gdb will be surprised when threads seem to continue -to stop at it. All of these situations produce spurious signal 5 traps; -if this happens, just type @samp{cont}. If it becomes a nuisance, use -@samp{handle 5 nostop}. (It will ask if you are sure. You are.) - -There is no way in GDB to store a float in a register, as with -@kbd{set $s0 = 3.1416}. The identifier @kbd{$s0} denotes an integer, -and like any C expression which assigns to an integer variable, the -right-hand side is casted to type int. If you should need to do -something like this, you can assign the value to @kbd{@{float@} ($sp-4)} -and then do @kbd{set $s0 = $sp[-4]}. Same deal with @kbd{set $v0[69] = 6.9}. |