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1 | @c OBSOLETE |
2 | @c OBSOLETE @node Convex,,, Top | |
3 | @c OBSOLETE @appendix Convex-specific info | |
4 | @c OBSOLETE @cindex Convex notes | |
5 | @c OBSOLETE | |
6 | @c OBSOLETE Scalar registers are 64 bits long, which is a pain since | |
7 | @c OBSOLETE left half of an S register frequently contains noise. | |
8 | @c OBSOLETE Therefore there are two ways to obtain the value of an S register. | |
9 | @c OBSOLETE | |
10 | @c OBSOLETE @table @kbd | |
11 | @c OBSOLETE @item $s0 | |
12 | @c OBSOLETE returns the low half of the register as an int | |
13 | @c OBSOLETE | |
14 | @c OBSOLETE @item $S0 | |
15 | @c OBSOLETE returns the whole register as a long long | |
16 | @c OBSOLETE @end table | |
17 | @c OBSOLETE | |
18 | @c OBSOLETE You can print the value in floating point by using @samp{p/f $s0} or @samp{p/f $S0} | |
19 | @c OBSOLETE to print a single or double precision value. | |
20 | @c OBSOLETE | |
21 | @c OBSOLETE @cindex vector registers | |
22 | @c OBSOLETE Vector registers are handled similarly, with @samp{$V0} denoting the whole | |
23 | @c OBSOLETE 64-bit register and @kbd{$v0} denoting the 32-bit low half; @samp{p/f $v0} | |
24 | @c OBSOLETE or @samp{p/f $V0} can be used to examine the register in floating point. | |
25 | @c OBSOLETE The length of the vector registers is taken from @samp{$vl}. | |
26 | @c OBSOLETE | |
27 | @c OBSOLETE Individual elements of a vector register are denoted in the obvious way; | |
28 | @c OBSOLETE @samp{print $v3[9]} prints the tenth element of register @kbd{v3}, and | |
29 | @c OBSOLETE @samp{set $v3[9] = 1234} alters it. | |
30 | @c OBSOLETE | |
31 | @c OBSOLETE @kbd{$vl} and @kbd{$vs} are int, and @kbd{$vm} is an int vector. | |
32 | @c OBSOLETE Elements of @kbd{$vm} can't be assigned to. | |
33 | @c OBSOLETE | |
34 | @c OBSOLETE @cindex communication registers | |
35 | @c OBSOLETE @kindex info comm-registers | |
36 | @c OBSOLETE Communication registers have names @kbd{$C0 .. $C63}, with @kbd{$c0 .. $c63} | |
37 | @c OBSOLETE denoting the low-order halves. @samp{info comm-registers} will print them | |
38 | @c OBSOLETE all out, and tell which are locked. (A communication register is | |
39 | @c OBSOLETE locked when a value is sent to it, and unlocked when the value is | |
40 | @c OBSOLETE received.) Communication registers are, of course, global to all | |
41 | @c OBSOLETE threads, so it does not matter what the currently selected thread is. | |
42 | @c OBSOLETE @samp{info comm-reg @var{name}} prints just that one communication | |
43 | @c OBSOLETE register; @samp{name} may also be a communication register number | |
44 | @c OBSOLETE @samp{nn} or @samp{0xnn}. | |
45 | @c OBSOLETE @samp{info comm-reg @var{address}} prints the contents of the resource | |
46 | @c OBSOLETE structure at that address. | |
47 | @c OBSOLETE | |
48 | @c OBSOLETE @kindex info psw | |
49 | @c OBSOLETE The command @samp{info psw} prints the processor status word @kbd{$ps} | |
50 | @c OBSOLETE bit by bit. | |
51 | @c OBSOLETE | |
52 | @c OBSOLETE @kindex set base | |
53 | @c OBSOLETE GDB normally prints all integers in base 10, but the leading | |
54 | @c OBSOLETE @kbd{0x80000000} of pointers is intolerable in decimal, so the default | |
55 | @c OBSOLETE output radix has been changed to try to print addresses appropriately. | |
56 | @c OBSOLETE The @samp{set base} command can be used to change this. | |
57 | @c OBSOLETE | |
58 | @c OBSOLETE @table @code | |
59 | @c OBSOLETE @item set base 10 | |
60 | @c OBSOLETE Integer values always print in decimal. | |
61 | @c OBSOLETE | |
62 | @c OBSOLETE @item set base 16 | |
63 | @c OBSOLETE Integer values always print in hex. | |
64 | @c OBSOLETE | |
65 | @c OBSOLETE @item set base | |
66 | @c OBSOLETE Go back to the initial state, which prints integer values in hex if they | |
67 | @c OBSOLETE look like pointers (specifically, if they start with 0x8 or 0xf in the | |
68 | @c OBSOLETE stack), otherwise in decimal. | |
69 | @c OBSOLETE @end table | |
70 | @c OBSOLETE | |
71 | @c OBSOLETE @kindex set pipeline | |
72 | @c OBSOLETE When an exception such as a bus error or overflow happens, usually the PC | |
73 | @c OBSOLETE is several instructions ahead by the time the exception is detected. | |
74 | @c OBSOLETE The @samp{set pipe} command will disable this. | |
75 | @c OBSOLETE | |
76 | @c OBSOLETE @table @code | |
77 | @c OBSOLETE @item set pipeline off | |
78 | @c OBSOLETE Forces serial execution of instructions; no vector chaining and no | |
79 | @c OBSOLETE scalar instruction overlap. With this, exceptions are detected with | |
80 | @c OBSOLETE the PC pointing to the instruction after the one in error. | |
81 | @c OBSOLETE | |
82 | @c OBSOLETE @item set pipeline on | |
83 | @c OBSOLETE Returns to normal, fast, execution. This is the default. | |
84 | @c OBSOLETE @end table | |
85 | @c OBSOLETE | |
86 | @c OBSOLETE @cindex parallel | |
87 | @c OBSOLETE In a parallel program, multiple threads may be executing, each | |
88 | @c OBSOLETE with its own registers, stack, and local memory. When one of them | |
89 | @c OBSOLETE hits a breakpoint, that thread is selected. Other threads do | |
90 | @c OBSOLETE not run while the thread is in the breakpoint. | |
91 | @c OBSOLETE | |
92 | @c OBSOLETE @kindex 1cont | |
93 | @c OBSOLETE The selected thread can be single-stepped, given signals, and so | |
94 | @c OBSOLETE on. Any other threads remain stopped. When a @samp{cont} command is given, | |
95 | @c OBSOLETE all threads are resumed. To resume just the selected thread, use | |
96 | @c OBSOLETE the command @samp{1cont}. | |
97 | @c OBSOLETE | |
98 | @c OBSOLETE @kindex thread | |
99 | @c OBSOLETE The @samp{thread} command will show the active threads and the | |
100 | @c OBSOLETE instruction they are about to execute. The selected thread is marked | |
101 | @c OBSOLETE with an asterisk. The command @samp{thread @var{n}} will select thread @var{n}, | |
102 | @c OBSOLETE shifting the debugger's attention to it for single-stepping, | |
103 | @c OBSOLETE registers, local memory, and so on. | |
104 | @c OBSOLETE | |
105 | @c OBSOLETE @kindex info threads | |
106 | @c OBSOLETE The @samp{info threads} command will show what threads, if any, have | |
107 | @c OBSOLETE invisibly hit breakpoints or signals and are waiting to be noticed. | |
108 | @c OBSOLETE | |
109 | @c OBSOLETE @kindex set parallel | |
110 | @c OBSOLETE The @samp{set parallel} command controls how many threads can be active. | |
111 | @c OBSOLETE | |
112 | @c OBSOLETE @table @code | |
113 | @c OBSOLETE @item set parallel off | |
114 | @c OBSOLETE One thread. Requests by the program that other threads join in | |
115 | @c OBSOLETE (spawn and pfork instructions) do not cause other threads to start up. | |
116 | @c OBSOLETE This does the same thing as the @samp{limit concurrency 1} command. | |
117 | @c OBSOLETE | |
118 | @c OBSOLETE @item set parallel fixed | |
119 | @c OBSOLETE All CPUs are assigned to your program whenever it runs. When it | |
120 | @c OBSOLETE executes a pfork or spawn instruction, it begins parallel execution | |
121 | @c OBSOLETE immediately. This does the same thing as the @samp{mpa -f} command. | |
122 | @c OBSOLETE | |
123 | @c OBSOLETE @item set parallel on | |
124 | @c OBSOLETE One or more threads. Spawn and pfork cause CPUs to join in when and if | |
125 | @c OBSOLETE they are free. This is the default. It is very good for system | |
126 | @c OBSOLETE throughput, but not very good for finding bugs in parallel code. If you | |
127 | @c OBSOLETE suspect a bug in parallel code, you probably want @samp{set parallel fixed.} | |
128 | @c OBSOLETE @end table | |
129 | @c OBSOLETE | |
130 | @c OBSOLETE @subsection Limitations | |
131 | @c OBSOLETE | |
132 | @c OBSOLETE WARNING: Convex GDB evaluates expressions in long long, because S | |
133 | @c OBSOLETE registers are 64 bits long. However, GDB expression semantics are not | |
134 | @c OBSOLETE exactly C semantics. This is a bug, strictly speaking, but it's not one I | |
135 | @c OBSOLETE know how to fix. If @samp{x} is a program variable of type int, then it | |
136 | @c OBSOLETE is also type int to GDB, but @samp{x + 1} is long long, as is @samp{x + y} | |
137 | @c OBSOLETE or any other expression requiring computation. So is the expression | |
138 | @c OBSOLETE @samp{1}, or any other constant. You only really have to watch out for | |
139 | @c OBSOLETE calls. The innocuous expression @samp{list_node (0x80001234)} has an | |
140 | @c OBSOLETE argument of type long long. You must explicitly cast it to int. | |
141 | @c OBSOLETE | |
142 | @c OBSOLETE It is not possible to continue after an uncaught fatal signal by using | |
143 | @c OBSOLETE @samp{signal 0}, @samp{return}, @samp{jump}, or anything else. The difficulty is with | |
144 | @c OBSOLETE Unix, not GDB. | |
145 | @c OBSOLETE | |
146 | @c OBSOLETE I have made no big effort to make such things as single-stepping a | |
147 | @c OBSOLETE @kbd{join} instruction do something reasonable. If the program seems to | |
148 | @c OBSOLETE hang when doing this, type @kbd{ctrl-c} and @samp{cont}, or use | |
149 | @c OBSOLETE @samp{thread} to shift to a live thread. Single-stepping a @kbd{spawn} | |
150 | @c OBSOLETE instruction apparently causes new threads to be born with their T bit set; | |
151 | @c OBSOLETE this is not handled gracefully. When a thread has hit a breakpoint, other | |
152 | @c OBSOLETE threads may have invisibly hit the breakpoint in the background; if you | |
153 | @c OBSOLETE clear the breakpoint gdb will be surprised when threads seem to continue | |
154 | @c OBSOLETE to stop at it. All of these situations produce spurious signal 5 traps; | |
155 | @c OBSOLETE if this happens, just type @samp{cont}. If it becomes a nuisance, use | |
156 | @c OBSOLETE @samp{handle 5 nostop}. (It will ask if you are sure. You are.) | |
157 | @c OBSOLETE | |
158 | @c OBSOLETE There is no way in GDB to store a float in a register, as with | |
159 | @c OBSOLETE @kbd{set $s0 = 3.1416}. The identifier @kbd{$s0} denotes an integer, | |
160 | @c OBSOLETE and like any C expression which assigns to an integer variable, the | |
161 | @c OBSOLETE right-hand side is casted to type int. If you should need to do | |
162 | @c OBSOLETE something like this, you can assign the value to @kbd{@{float@} ($sp-4)} | |
163 | @c OBSOLETE and then do @kbd{set $s0 = $sp[-4]}. Same deal with @kbd{set $v0[69] = 6.9}. | |
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