NAME

core.ops - Parrot Core Ops

DESCRIPTION

Parrot's core library of ops.

Core operations are primarily flow control and interpreter introspection.

Basic ops

These are the fundamental operations. Please note: These opcodes must not be moved; they must have exactly these opcode numbers. Opcodes ending with underscores are for internal use only; don't emit these opcodes.

end(): Halts the interpreter. (Must be op #0, CORE_OPS_end). See also exit.
noop(): Does nothing other than waste an iota of time and 32 bits of bytecode space. (Must be op #1, CORE_OPS_noop)
cpu_ret(): Emit a cpu return instruction. This is used to return from CGP core to JIT code. Note: Do not use this opcode. It is for internal use only. (Must be op #2, CORE_OPS_cpu_ret)
check_events(): Check the event queue and run event handlers if there are unhandled events. Note: This opcode is mainly for testing. It should not be necessary to ever use it explicitly. (Must be op #3, CORE_OPS_check_events).
check_events__(): Check the event queue and run event handlers if there are unhandled events. Note: Do not use this opcode. It is for internal use only. (Must be op #4, CORE_OPS_check_events__).
wrapper__(): Internal opcode to wrap unknown ops from loaded opcode libs. Don't use. (Must be op #5, CORE_OPS_wrapper__).
prederef__(): Internal opcode to prederef opcodes on the fly. Don't use. (Must be op #6, CORE_OPS_prederef__).
reserved(inconst INT): Reserve 1 more fix entry.
load_bytecode(in STR): Load Parrot bytecode from file $1, and RT#42381 search the library path to locate the file.

Control flow

The control flow opcodes check conditions and manage program flow.

branch(label INT): Branch forward or backward by the amount in $1.
branch_cs(in STR): Intersegment branch to location in fixup table named $1.
bsr(label INT): Branch to the location specified by $1. Push the current location onto the call stack for later returning.
ret(): Pop the location off the top of the call stack and go there.
jsr(label INT): Jump to the location specified by register $1. Push the current location onto the call stack for later returning.
jump(label INT): Jump to the address held in register $1.
enternative(): Internal opcode used to jump from normal bytecode into a JITted version.

Conditional branch operations

These operations perform a conditional relative branch. If the condition is met, the branch happens. Otherwise control falls to the next operation.

if(invar INT, labelconst INT)
if(invar NUM, labelconst INT)
if(invar PMC, labelconst INT)
if(invar STR, labelconst INT): Check register $1. If true, branch by $2.
unless(invar INT, labelconst INT)
unless(invar NUM, labelconst INT)
unless(invar PMC, labelconst INT)
unless(invar STR, labelconst INT): Check register $1. If false, branch by $2.

Subroutine operations

These operations are used to generate and call subroutines and continuations.

invokecc(invar PMC): Call the subroutine in $1 and generate a new return continuation, if needed. For example, a NCI subroutine which executes code in some C library will not create a continuation, nor will anything but the first call to a coroutine.
invoke(invar PMC, invar PMC): Call the subroutine in $1 and use continuation $2.
yield(): Yield results from a coroutine.
tailcall(invar PMC): Call the subroutine in $1 and use the current continuation as the subs continuation.
returncc(): Return from the sub or method via the current continuation.
newclosure(out PMC, invar PMC): Create a closure of the given subroutine PMC by cloning the sub's state.

Function argument opcode

Implementations of function argument and params handling

set_args(inconst PMC /* , ... */): Define arguments for the next function call.
get_results(inconst PMC /* , ... */): Define return values for the next function call.
get_params(inconst PMC /* , ... */): Define function parameters for this subroutine.
set_returns(inconst PMC /* , ... */): Define return results for the subroutine return statement.; For all of these opcodes the passed invar PMC constant is the string representation of a FixedIntegerArray with one flag word per argument. The flags are documented currently in include/parrot/enum.h only.; After this argument a variable amount of arguments must follow according to the elements of the signature array.
result_info(out PMC): Returns the get_results signature PMC of the caller. This PMC is a FixedIntegerPMCArray. The number of elements of this PMC is equal to the number of return values that are expected. The individual bits per entry are specified in docs/pdds/pdd03_calling_conventions.pod.

Address manipulation

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set_addr(out INT, labelconst INT): Sets register $1 to the current address plus the offset $2.
set_addr(invar PMC, labelconst INT): Sets PMC in register $1 to the current address plus the offset $2.
set_addr(invar PMC, labelvar INT): Sets PMC in register $1 to the absolute address $2 obtained from get_addr.
get_addr(out INT, invar PMC): Sets $1 to the absolute address of the Sub PMC $2.

Exception handling

push_eh(labelconst INT): Create an exception handler for the given catch label and push it onto the control stack.
clear_eh(): Clear out the most recently placed exception.
throw(invar PMC): Throw the exception in $1.
rethrow(invar PMC): Only valid inside an exception handler. Rethrow the exception $1.
die(in INT, in INT): Die with severity $1 and error $2. If severity is .EXCEPT_DOOMED, call _exit($2). The latter isn't catchable.
exit(in INT): Exit the interpreter with exit_status $1. If you want to communicate an extended exit status, create an exception with severity EXCEPT_exit and throw it.
pushmark(in INT): Push a mark labeled $1 onto the dynamic environment.
popmark(in INT): Pop all items off the dynamic environment to the given mark.
pushaction(invar PMC): Push the given Sub PMC $1 onto the dynamic environment. If the dynamic environment is unwound due to a popmark, subroutine return, or an exception, the subroutine will be invoked with an integer argument: 0 means a normal return; 1 means an exception has been raised.

Interpreter operations

These operations inspect or modify the interpreter itself, possibly affecting its subsequent operation.

debug(in INT): If $1 is zero, turn off debugging. Otherwise turn debug flag $1 on.
bounds(in INT): If $1 is zero, turn off byte code bounds checking. Otherwise turn it on.
profile(in INT): If $1 is zero, turn off profiling. Otherwise turn it on.
trace(in INT): If $1 is zero, turn off tracing. Otherwise turn trace flag $1 on.
gc_debug(in INT): If $1 is zero, turn off GC_DEBUG. Otherwise turn it on.
interpinfo: Fetch some piece of information about the interpreter and put it in $1. Possible values for $2 are defined in runtime/parrot/include/interpinfo.pasm. The valid constants for each return value are:
warningson(in INT): Turns on warnings categories. Categories already turned on will stay on. Initial setting is currently all warnings off. Include warnings.pasm to access the categories. They are:; To turn on multiple categories, OR the category numbers together.
warningsoff(in INT): Turns off warnings categories. Categories already turned off will stay off. See the documentation for warningson for category numbers.
errorson(in INT): Turns on error categories. Categories already turned on will stay on. To access these from PASM, include errors.pasm. The current categories are:; To turn on multiple categories, OR the category numbers together.
errorsoff(in INT): Turns off errors categories. Categories already turned off will stay off. See the documentation for errorson for category numbers.
runinterp(invar PMC, label INT): Run the code starting at offset $2 within interpreter $1.
getinterp(out PMC): Get the current ParrotInterpreter.

Dead Object Detection/Garbage Collection

Opcodes that interact with the DOD and GC subsystems.

sweep(inconst INT): Triggers a DOD run, based on the value of $1, where:
collect(): Trigger a garbage collection.
sweepoff(): Disable DOD sweeps. (Nestable)
sweepon(): Re-enable DOD sweeps.
collectoff(): Disable GC runs (nestable).
collecton(): Re-enable GC.
needs_destroy(invar PMC): Mark the PMC wanting destruction as soon as possible, for example when unused during the lazy sweep, triggered by sweep 0.

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Native Call Interface

Opcodes for interfacing with C functions in shared libraries.

loadlib(out PMC, in STR): Load a dynamic link library named $2 and store it in $1.
dlfunc(out PMC, invar PMC, in STR, in STR): Look up symbol $3 in library $2 with signature $4, and put the corresponding sub object in $1. Note that you need the signature so we can build or find an appropriate thunking function.
dlvar(out PMC, invar PMC, in STR): Look up symbol $3 in library $2. We assume that this is actually a variable address rather than a function address, and build an UnManagedStruct PMC and stick the address into its data pointer.
compreg(out PMC, in STR): Get a compiler for source type $2.
compreg(in STR, invar PMC): Register the sub $2 as a compiler for source type $1. $2 is either a NCI PMC with signature pIt or a PASM Sub.
new_callback(out PMC, invar PMC, invar PMC, in STR): Create a callback stub $1 for PASM subroutine $2 with userdata $3 and callback function signature $4. Only 2 argument signatures with signature chars U[1iscpt] or [1iscpt]U are handled currently. But these cover a lot of callback signatures. Please note that the userdata PMC U has to be handled transparently by the caller of the callback function.

COPYRIGHT

LICENSE

This program is free software. It is subject to the same license as the Parrot interpreter itself.