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changeset 3161:145bbd061aa0

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defs/os9.d: Expand comment about level2 block/system map flags
author Neal Crook <foofoobedoo@gmail.com>
date Thu, 06 Apr 2017 21:56:47 +0100
parents b79920779783
children c44cd20907bd
files defs/os9.d
diffstat 1 files changed, 5 insertions(+), 1 deletions(-) [+]
line wrap: on
line diff
--- a/defs/os9.d	Thu Apr 06 21:53:57 2017 +0100
+++ b/defs/os9.d	Thu Apr 06 21:56:47 2017 +0100
@@ -633,7 +633,11 @@
 D.NMI          RMB       2
 
 *************************
-* Level 2 Block Map flags
+* Level 2 flags used for bytes in the memory block map at D.BlkMap
+* and for bytes in the system memory map at D.SysMem.
+* A value of 0 indicates an unused/unassigned block.
+* In the code, block assignment often involves incrementing a value
+* from 0 to 1 rather than explict use of RAMinUse.
 *
 NotRAM         EQU       %10000000           Block Not RAM flag
 VidRAM         EQU       %00000100           Block is being used as Video RAM