src/runtime/dynbind.c

   1 /*
   2  * support for dynamic binding from C
   3  */
   4
   5 /*
   6  * This software is part of the SBCL system. See the README file for
   7  * more information.
   8  *
   9  * This software is derived from the CMU CL system, which was
  10  * written at Carnegie Mellon University and released into the
  11  * public domain. The software is in the public domain and is
  12  * provided with absolutely no warranty. See the COPYING and CREDITS
  13  * files for more information.
  14  */
  15
  16 #include "runtime.h"
  17 #include "sbcl.h"
  18 #include "globals.h"
  19 #include "dynbind.h"
  20 #include "thread.h"
  21 #include "genesis/symbol.h"
  22 #include "genesis/binding.h"
  23 #include "genesis/thread.h"
  24
  25 #if defined(BINDING_STACK_POINTER)
  26 #define GetBSP() ((struct binding *)SymbolValue(BINDING_STACK_POINTER,thread))
  27 #define SetBSP(value) SetSymbolValue(BINDING_STACK_POINTER, (lispobj)(value),thread)
  28 #else
  29 #define GetBSP() ((struct binding *)current_binding_stack_pointer)
  30 #define SetBSP(value) (current_binding_stack_pointer=(lispobj *)(value))
  31 #endif
  32
  33 void bind_variable(lispobj symbol, lispobj value, void *th)
  34 {
  35     lispobj old_tl_value;
  36     struct binding *binding;
  37     struct thread *thread=(struct thread *)th;
  38 #ifdef LISP_FEATURE_SB_THREAD
  39     struct symbol *sym=(struct symbol *)native_pointer(symbol);
  40 #endif
  41     binding = GetBSP();
  42     SetBSP(binding+1);
  43 #ifdef LISP_FEATURE_SB_THREAD
  44     if(!sym->tls_index) {
  45         sym->tls_index=SymbolValue(FREE_TLS_INDEX,0);
  46         SetSymbolValue(FREE_TLS_INDEX,
  47                        make_fixnum(fixnum_value(sym->tls_index)+1),0);
  48     }
  49 #endif
  50     old_tl_value=SymbolTlValue(symbol,thread);
  51     binding->value = old_tl_value;
  52     binding->symbol = symbol;
  53     SetTlSymbolValue(symbol, value,thread);
  54 }
  55
  56 void
  57 unbind(void *th)
  58 {
  59     struct thread *thread=(struct thread *)th;
  60     struct binding *binding;
  61     lispobj symbol;
  62
  63     binding = GetBSP() - 1;
  64
  65     symbol = binding->symbol;
  66
  67     SetTlSymbolValue(symbol, binding->value,thread);
  68
  69     binding->symbol = 0;
  70
  71     SetBSP(binding);
  72 }
  73
  74 void
  75 unbind_to_here(lispobj *bsp,void *th)
  76 {
  77     struct thread *thread=(struct thread *)th;
  78     struct binding *target = (struct binding *)bsp;
  79     struct binding *binding = GetBSP();
  80     lispobj symbol;
  81
  82     while (target < binding) {
  83         binding--;
  84
  85         symbol = binding->symbol;
  86         if (symbol) {
  87             SetTlSymbolValue(symbol, binding->value,thread);
  88             binding->symbol = 0;
  89         }
  90     }
  91     SetBSP(binding);
  92 }