64 lines
1.6 KiB
C++
64 lines
1.6 KiB
C++
namespace factor
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{
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/* Assembly code makes assumptions about the layout of this struct:
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- callstack_top field is 0
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- callstack_bottom field is 1
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- datastack field is 2
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- retainstack field is 3 */
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struct context {
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/* C stack pointer on entry */
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stack_frame *callstack_top;
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stack_frame *callstack_bottom;
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/* current datastack top pointer */
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cell datastack;
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/* current retain stack top pointer */
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cell retainstack;
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/* saved contents of ds register on entry to callback */
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cell datastack_save;
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/* saved contents of rs register on entry to callback */
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cell retainstack_save;
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/* callback-bottom stack frame, or NULL for top-level context.
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When nest_stacks() is called, callstack layout with callbacks
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is as follows:
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[ C function ]
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[ callback stub in code heap ] <-- this is the magic frame
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[ native frame: c_to_factor() ]
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[ callback quotation frame ] <-- first call frame in call stack
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magic frame is retained so that it's XT can be traced and forwarded. */
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stack_frame *magic_frame;
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/* memory region holding current datastack */
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segment *datastack_region;
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/* memory region holding current retain stack */
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segment *retainstack_region;
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/* saved special_objects slots on entry to callback */
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cell catchstack_save;
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cell current_callback_save;
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context *next;
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};
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#define ds_bot (ctx->datastack_region->start)
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#define ds_top (ctx->datastack_region->end)
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#define rs_bot (ctx->retainstack_region->start)
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#define rs_top (ctx->retainstack_region->end)
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DEFPUSHPOP(d,ds)
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DEFPUSHPOP(r,rs)
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VM_C_API void nest_stacks(stack_frame *magic_frame, factor_vm *vm);
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VM_C_API void unnest_stacks(factor_vm *vm);
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}
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