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author | Tristan Gingold <tgingold@free.fr> | 2015-09-04 21:52:38 +0200 |
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committer | Tristan Gingold <tgingold@free.fr> | 2015-09-04 21:52:38 +0200 |
commit | 8520993b4d1eadefa488dfc96dff25333f1b19db (patch) | |
tree | 818d4fe917d3e6b765932ed3d1ab1ee70dc3c508 /src/grt/grt-stack2.ads | |
parent | 2d8f611cb63b72aa0373efe0ffa0df47e25519c9 (diff) | |
download | ghdl-8520993b4d1eadefa488dfc96dff25333f1b19db.tar.gz ghdl-8520993b4d1eadefa488dfc96dff25333f1b19db.tar.bz2 ghdl-8520993b4d1eadefa488dfc96dff25333f1b19db.zip |
Suppress stack switching; save process state in secondary stack.
Diffstat (limited to 'src/grt/grt-stack2.ads')
-rw-r--r-- | src/grt/grt-stack2.ads | 35 |
1 files changed, 29 insertions, 6 deletions
diff --git a/src/grt/grt-stack2.ads b/src/grt/grt-stack2.ads index b3de6b76d..1c0c79afe 100644 --- a/src/grt/grt-stack2.ads +++ b/src/grt/grt-stack2.ads @@ -26,18 +26,41 @@ with System; with Grt.Types; use Grt.Types; -- Secondary stack management. +-- The secondary stack is used by vhdl to return object from function whose +-- type is unconstrained. This is less efficient than returning the object +-- on the stack, but compatible with any ABI. +-- +-- The management is very simple: mark and release. Allocate reserved a +-- chunk of memory from the secondary stack, Release deallocate all the +-- memory allocated since the mark. + package Grt.Stack2 is - type Stack2_Ptr is new System.Address; - Null_Stack2_Ptr : constant Stack2_Ptr := Stack2_Ptr (System.Null_Address); + -- Designate a secondary stack. + type Stack2_Ptr is private; - type Mark_Id is new Integer_Address; + -- Indicator for a non-existing secondary stack. Create never return that + -- value. + Null_Stack2_Ptr : constant Stack2_Ptr; + + -- Type of a mark. + type Mark_Id is private; + -- Get the current mark, which indicate a current amount of allocated + -- memory. function Mark (S : Stack2_Ptr) return Mark_Id; + + -- Deallocate (free) all the memory allocated since MARK. procedure Release (S : Stack2_Ptr; Mark : Mark_Id); + + -- Allocate SIZE bytes (aligned on the maximum alignment) on stack S. function Allocate (S : Stack2_Ptr; Size : Ghdl_Index_Type) - return System.Address; + return System.Address; + + -- Create a secondary stack. function Create return Stack2_Ptr; +private + type Stack2_Ptr is new System.Address; + Null_Stack2_Ptr : constant Stack2_Ptr := Stack2_Ptr (System.Null_Address); - -- Check S is empty. - procedure Check_Empty (S : Stack2_Ptr); + type Mark_Id is new Integer_Address; end Grt.Stack2; |