6 void factor_vm::reset_datastack()
8 ds = ds_bot - sizeof(cell);
11 void factor_vm::reset_retainstack()
13 rs = rs_bot - sizeof(cell);
16 static const cell stack_reserved = (64 * sizeof(cell));
18 void factor_vm::fix_stacks()
20 if(ds + sizeof(cell) < ds_bot || ds + stack_reserved >= ds_top) reset_datastack();
21 if(rs + sizeof(cell) < rs_bot || rs + stack_reserved >= rs_top) reset_retainstack();
24 /* called before entry into foreign C code. Note that ds and rs might
25 be stored in registers, so callbacks must save and restore the correct values */
26 void factor_vm::save_stacks()
31 ctx->retainstack = rs;
35 context *factor_vm::alloc_context()
41 new_context = unused_contexts;
42 unused_contexts = unused_contexts->next;
46 new_context = new context;
47 new_context->datastack_region = new segment(ds_size,false);
48 new_context->retainstack_region = new segment(rs_size,false);
54 void factor_vm::dealloc_context(context *old_context)
56 old_context->next = unused_contexts;
57 unused_contexts = old_context;
60 /* called on entry into a compiled callback */
61 void factor_vm::nest_stacks(stack_frame *magic_frame)
63 context *new_ctx = alloc_context();
65 new_ctx->callstack_bottom = (stack_frame *)-1;
66 new_ctx->callstack_top = (stack_frame *)-1;
68 /* note that these register values are not necessarily valid stack
69 pointers. they are merely saved non-volatile registers, and are
70 restored in unnest_stacks(). consider this scenario:
71 - factor code calls C function
72 - C function saves ds/cs registers (since they're non-volatile)
73 - C function clobbers them
74 - C function calls Factor callback
75 - Factor callback returns
76 - C function restores registers
77 - C function returns to Factor code */
78 new_ctx->datastack_save = ds;
79 new_ctx->retainstack_save = rs;
81 new_ctx->magic_frame = magic_frame;
83 /* save per-callback userenv */
84 new_ctx->current_callback_save = userenv[CURRENT_CALLBACK_ENV];
85 new_ctx->catchstack_save = userenv[CATCHSTACK_ENV];
94 void nest_stacks(stack_frame *magic_frame, factor_vm *myvm)
96 return myvm->nest_stacks(magic_frame);
99 /* called when leaving a compiled callback */
100 void factor_vm::unnest_stacks()
102 ds = ctx->datastack_save;
103 rs = ctx->retainstack_save;
105 /* restore per-callback userenv */
106 userenv[CURRENT_CALLBACK_ENV] = ctx->current_callback_save;
107 userenv[CATCHSTACK_ENV] = ctx->catchstack_save;
109 context *old_ctx = ctx;
111 dealloc_context(old_ctx);
114 void unnest_stacks(factor_vm *myvm)
116 return myvm->unnest_stacks();
119 /* called on startup */
120 void factor_vm::init_stacks(cell ds_size_, cell rs_size_)
125 unused_contexts = NULL;
128 bool factor_vm::stack_to_array(cell bottom, cell top)
130 fixnum depth = (fixnum)(top - bottom + sizeof(cell));
136 array *a = allot_array_internal<array>(depth / sizeof(cell));
137 memcpy(a + 1,(void*)bottom,depth);
138 dpush(tag<array>(a));
143 void factor_vm::primitive_datastack()
145 if(!stack_to_array(ds_bot,ds))
146 general_error(ERROR_DS_UNDERFLOW,F,F,NULL);
149 void factor_vm::primitive_retainstack()
151 if(!stack_to_array(rs_bot,rs))
152 general_error(ERROR_RS_UNDERFLOW,F,F,NULL);
155 /* returns pointer to top of stack */
156 cell factor_vm::array_to_stack(array *array, cell bottom)
158 cell depth = array_capacity(array) * sizeof(cell);
159 memcpy((void*)bottom,array + 1,depth);
160 return bottom + depth - sizeof(cell);
163 void factor_vm::primitive_set_datastack()
165 ds = array_to_stack(untag_check<array>(dpop()),ds_bot);
168 void factor_vm::primitive_set_retainstack()
170 rs = array_to_stack(untag_check<array>(dpop()),rs_bot);
173 /* Used to implement call( */
174 void factor_vm::primitive_check_datastack()
176 fixnum out = to_fixnum(dpop());
177 fixnum in = to_fixnum(dpop());
178 fixnum height = out - in;
179 array *saved_datastack = untag_check<array>(dpop());
180 fixnum saved_height = array_capacity(saved_datastack);
181 fixnum current_height = (ds - ds_bot + sizeof(cell)) / sizeof(cell);
182 if(current_height - height != saved_height)
187 for(i = 0; i < saved_height - in; i++)
189 if(((cell *)ds_bot)[i] != array_nth(saved_datastack,i))