HP 3000 Manuals HP 3000 Manuals
HPENBLTRAP
NM callable only.
Selectively enables or disables arithmetic traps.
Syntax
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| |
| I32V I32 |
| HPENBLTRAP(mask,oldmask); |
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Parameters
mask 32-bit signed integer by value (required)
Passes a value indicating which arithmetic traps
are enabled and which are not:
* If a bit is on (=1), the corresponding trap
is enabled.
* If a bit is off (=0), the corresponding trap
is disabled.
The bits and their associated arithmetic errors
are:
Bits Value/Meaning
31:1 3000 mode floating-point divide by zero
30:1 Integer divide by zero
29:1 3000 mode floating-point underflow
28:1 3000 mode floating-point overflow
27:1 Integer overflow
26:1 3000 mode double-precision overflow
25:1 3000 mode double-precision underflow
24:1 3000 mode double-precision divide by zero
23:1 Decimal overflow
22:1 Invalid ASCII digit
21:1 Invalid decimal digit
19:2 Reserved for the operating system
18:1 Decimal divide by zero
17:1 IEEE floating-point, inexact result
16:1 IEEE floating-point underflow
Table 4-19. (cont.)
Bits Value/Meaning
15:1 IEEE floating-point overflow
14:1 IEEE floating-point divide by zero
13:1 IEEE floating-point, invalid operation
12:1 Range errors
11:1 Software-detected NIL pointer reference
10:1 Software-detected misaligned result of pointer
arithmetic or error in conversion from long pointer to
short pointer
9:1 Unimplemented condition traps
8:1 Paragraph stack overflow
7:1 3000 mode packed decimal error
1:7 Reserved for MPE/iX
0:1 Assertion trap
NOTE The following apply to various trap conditions represented in the
mask parameter:
* Native mode supports two floating-point formats: IEEE and
3000 mode. Both execute in native mode, but 3000 mode
performs
HP 3000 type manipulations. Since it is possible to use
both formats during program execution, there are separate
bits in the mask for enabling/disabling traps of these
formats.
* Some error conditions specified are not strictly arithmetic
traps (for example, range errors, nil pointers, and
paragraph stack overflow). However, many arithmetic
traps are caught by reserved instructions that raise
the conditional traps. For this reason, all are
enabled/disabled by HPENBLTRAP.
* Some of the instructions that raise conditional traps are
reserved to indicate some of the above trap conditions. A
nonreserved instruction is one not generated by a compiler.
If a nonreserved instruction causes a conditional trap, this
is reported as an unimplemented condition trap.
oldmask 32-bit signed integer by reference (required)
Returns the value of the previous mask to the
program.
Operation Notes
Allows selective enabling or disabling of arithmetic traps. It provides
more flexibility than the ARITRAP intrinsic, which collectively enables
or disables traps.
There is a difference between arming and enabling traps:
* Enabling a trap means that the occurrence of a trap condition is
not ignored.
* Arming a trap is required so that, on a trap condition, a
user-written routine is invoked and can take appropriate recovery
actions.
The following list summarizes what can occur when an arithmetic trap
condition arises:
* If a trap is both enabled and armed, the user-written trap handler
is invoked whenever a trap condition occurs.
* If a trap is enabled but not armed, one of two situations applies:
* If a Pascal/XL TRY statement has been executed, control is
passed to the recover block by doing an escape.
* If a Pascal/XL TRY statement has not been executed, an
error message is output and the process aborts.
* If a trap is disabled, irrespective of whether it is armed, the
trap is ignored, and execution of the process continues without
any interruption.
NOTE By default, all traps except IEEE floating-point exceptions are
enabled, and the system trap handler is armed. Many floating-point
operations result in an inexact result. Consequently, most
compiler libraries doing floating-point operations result in an
inexact trap if the IEEE inexact result trap is enabled.
Condition Codes
CCE (2) Request granted. All traps were originally
disabled.
CCG (0) Request granted. At least one trap was originally
enabled.
CCL (1) Not returned.
Related Information
Intrinsics None
Commands None
Manuals Trap Handling Programmer's Guide (32650-90026)