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remove the `late-bind' instruction

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* doc/ref/vm.texi: Minor fixes.

* libguile/vm-i-loader.c: Remove the unused `late-bind' instruction.
This commit is contained in:
Andy Wingo 2008-12-19 11:50:43 +01:00
parent 090d51edb2
commit d22fc3e4af
2 changed files with 11 additions and 24 deletions
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21
doc/ref/vm.texi
View file

@ -94,7 +94,7 @@ global memory (modules, global bindings, etc) that is shared among
other parts of Guile, including other VMs. other parts of Guile, including other VMs.
A VM has generic instructions, such as those to reference local A VM has generic instructions, such as those to reference local
variables, and instructions designed to support Guile's langauges -- variables, and instructions designed to support Guile's languages --
mathematical instructions that support the entire numerical tower, an mathematical instructions that support the entire numerical tower, an
inlined implementation of @code{cons}, etc. inlined implementation of @code{cons}, etc.
@ -108,7 +108,7 @@ The registers that a VM has are as follows:
In other architectures, the instruction pointer is sometimes called In other architectures, the instruction pointer is sometimes called
the ``program counter'' (pc). This set of registers is pretty typical the ``program counter'' (pc). This set of registers is pretty typical
for stack machines; their exact meanings in the context of Guile's Vm for stack machines; their exact meanings in the context of Guile's VM
is described below REFFIXME. is described below REFFIXME.
A virtual machine executes by loading a compiled procedure, and A virtual machine executes by loading a compiled procedure, and
@ -188,10 +188,11 @@ we return from this activation frame, we will jump back to this
@item MV return address @item MV return address
The @code{ip} to return to if this application returns multiple The @code{ip} to return to if this application returns multiple
values. For continuations that only accept one value, this value will values. For continuations that only accept one value, this value will
be @code{NULL}; for others, it will be an @code{ip} that expects that be @code{NULL}; for others, it will be an @code{ip} that points to a
the top value on the stack is an integer -- the number of values being multiple-value return address in the calling code. That code will
returned -- and that below that integer there are the values being expect the top value on the stack to be an integer -- the number of
returned. values being returned -- and that below that integer there are the
values being returned.
@item Dynamic link @item Dynamic link
This is the @code{fp} in effect before this program was applied. In This is the @code{fp} in effect before this program was applied. In
@ -435,7 +436,7 @@ same way:
@itemize @itemize
@item They take the Scheme object located on the stack and use it as @item They take the Scheme object located on the stack and use it as
the branch condition; the branch condition;
@item If the condition if false, then program execution continues with @item If the condition is false, then program execution continues with
the next instruction; the next instruction;
@item If the condition is true, then the instruction pointer is @item If the condition is true, then the instruction pointer is
increased by the offset passed as an argument to the branch increased by the offset passed as an argument to the branch
@ -493,18 +494,18 @@ In order to handle such bindings, each program has an @dfn{object
table} associated to it. This table (actually a Scheme vector) table} associated to it. This table (actually a Scheme vector)
contains all constant objects referenced by the program. The object contains all constant objects referenced by the program. The object
table of a program is initialized right before a program is loaded table of a program is initialized right before a program is loaded
with @var{load-program}. with @code{load-program}.
Variable objects are one such type of constant object: when a global Variable objects are one such type of constant object: when a global
binding is defined, a variable object is associated to it and that binding is defined, a variable object is associated to it and that
object will remain constant over time, even if the value bound to it object will remain constant over time, even if the value bound to it
changes. Therefore, toplevel bindings only need to be looked up once. changes. Therefore, toplevel bindings only need to be looked up once.
ThereafterReferences to the corresponding toplevel variables from within the ThereafterReferences to the corresponding toplevel variables from within the
program are then performed via the @var{object-ref} instruction and program are then performed via the @code{object-ref} instruction and
are almost as fast as local variable references. are almost as fast as local variable references.
Let us consider the following program (procedure) which references Let us consider the following program (procedure) which references
external bindings @code{frob} and @var{%magic}: external bindings @code{frob} and @code{%magic}:
@example @example
(lambda (x) (lambda (x)

14
libguile/vm-i-loader.c
View file

@ -208,20 +208,6 @@ VM_DEFINE_LOADER (define, "define")
NEXT; NEXT;
} }
VM_DEFINE_LOADER (late_bind, "late-bind")
{
SCM sym;
size_t len;
FETCH_LENGTH (len);
SYNC_REGISTER ();
sym = scm_from_locale_symboln ((char *)ip, len);
ip += len;
PUSH (sym);
NEXT;
}
/* /*
Local Variables: Local Variables:
c-file-style: "gnu" c-file-style: "gnu"