From 949b03ad96336f4658eb0050f58abd517dd79c79 Mon Sep 17 00:00:00 2001
From: Robert Sprowson <rsprowson@gitlab.riscosopen.org>
Date: Sat, 14 Mar 2020 11:57:40 +0000
Subject: [PATCH] Special case extension of aligned RMA claims
During ModHandReason_ClaimAligned care is taken to start on a multiple of 32 and end on a multiple of 32 + 16 (such that the next block in the heap would be at +20 same as plain ModHandReason_Claim would do). However, during a ModHandReason_ExtendBlock there's a possibility that those criteria can't be retained, due to having to move to a larger gap elsewhere, leaving the end at an inconvenient +36.
Similar allocation functions in other OS' don't guarantee to return an extended block with the same alignment, so take the position that for extends we always allocate a fresh block, copy the contents, and free the original. Shrinks are left in place.
Tested with a random allocator which juggles 16 aligned allocations 50,000 times.
Version 6.36. Tagged as 'Kernel-6_36'
---
VersionASM | 12 ++++++------
VersionNum | 20 ++++++++++----------
s/ModHand | 32 ++++++++++++++++++++++++++++++--
3 files changed, 46 insertions(+), 18 deletions(-)
diff --git a/VersionASM b/VersionASM
index 9f99a48..b6adce6 100644
--- a/VersionASM
+++ b/VersionASM
@@ -9,12 +9,12 @@
GBLS Module_ApplicationDate
GBLS Module_HelpVersion
GBLS Module_ComponentName
-Module_MajorVersion SETS "6.35"
-Module_Version SETA 635
+Module_MajorVersion SETS "6.36"
+Module_Version SETA 636
Module_MinorVersion SETS ""
-Module_Date SETS "02 Mar 2020"
-Module_ApplicationDate SETS "02-Mar-20"
+Module_Date SETS "18 Mar 2020"
+Module_ApplicationDate SETS "18-Mar-20"
Module_ComponentName SETS "Kernel"
-Module_FullVersion SETS "6.35"
-Module_HelpVersion SETS "6.35 (02 Mar 2020)"
+Module_FullVersion SETS "6.36"
+Module_HelpVersion SETS "6.36 (18 Mar 2020)"
END
diff --git a/VersionNum b/VersionNum
index 7317692..abcbea7 100644
--- a/VersionNum
+++ b/VersionNum
@@ -1,21 +1,21 @@
-/* (6.35)
+/* (6.36)
*
* This file is automatically maintained by srccommit, do not edit manually.
*
*/
-#define Module_MajorVersion_CMHG 6.35
+#define Module_MajorVersion_CMHG 6.36
#define Module_MinorVersion_CMHG
-#define Module_Date_CMHG 02 Mar 2020
+#define Module_Date_CMHG 18 Mar 2020
-#define Module_MajorVersion "6.35"
-#define Module_Version 635
+#define Module_MajorVersion "6.36"
+#define Module_Version 636
#define Module_MinorVersion ""
-#define Module_Date "02 Mar 2020"
+#define Module_Date "18 Mar 2020"
-#define Module_ApplicationDate "02-Mar-20"
+#define Module_ApplicationDate "18-Mar-20"
#define Module_ComponentName "Kernel"
-#define Module_FullVersion "6.35"
-#define Module_HelpVersion "6.35 (02 Mar 2020)"
-#define Module_LibraryVersionInfo "6:35"
+#define Module_FullVersion "6.36"
+#define Module_HelpVersion "6.36 (18 Mar 2020)"
+#define Module_LibraryVersionInfo "6:36"
diff --git a/s/ModHand b/s/ModHand
index 5b25590..61ddbb1 100644
--- a/s/ModHand
+++ b/s/ModHand
@@ -1151,14 +1151,42 @@ Module_ExtendBlock ROUT
Push "R0, r1, R3, lr"
ADD R3, R3, #31
- BIC R3, R3, #31
+ BICS R3, R3, #31
+ BMI %FT10 ; shrinks don't move the block
+ TST R2, #31 ; starts at 32*n
+ BEQ %FT30 ; => grow an aligned block
+10
MOV R0, #HeapReason_ExtendBlock
BL DoRMAHeapOpWithExtension
-
+20
STRVS R0, [stack]
Pull "R0, r1, R3, lr"
B SLVK_TestV
+30
+ LDR R0, [R2, #-4] ; grow may cause move, so always move rather than lose the carefully
+ SUB R0, R0, #4 ; arranged next block alignment from RMAClaim_ChunkAligned
+ Push "R0, R2"
+ ADD R3, R0, R3
+ BL RMAClaim_Chunk
+ ADDVS SP, SP, #4*2
+ BVS %BT20
+
+ Pull "R0, R3" ; size, old block
+ Push "R2" ; new block
+40
+ SUBS R0, R0, #4
+ LDRPL LR, [R3, R0]
+ STRPL LR, [R2, R0]
+ BPL %BT40
+
+ MOV R0, #HeapReason_Free
+ MOV R1, #RMAAddress
+ MOV R2, R3
+ SWI XOS_Heap ; free old
+
+ Pull "R2" ; return new
+ B %BT20
;*************************************************************
; New Incarnation
--
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