[sdcc-devel] [ sdcc-Feature Requests-1859849 ] Volatile Direct Pointer not optimized

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Feature Requests item #1859849, was opened at 2007-12-28 20:48
Message generated for change (Comment added) made by maartenbrock
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>Category: None
Group: None
Status: Open
Priority: 5
Private: No
Submitted By: Nobody/Anonymous (nobody)
Assigned to: Nobody/Anonymous (nobody)
Summary: Volatile Direct Pointer not optimized

Initial Comment:
Accessing memory using a construct like
  (* (volatile xdata TestStruct *)0xF000).Var1
(where TestStruct is a struct) generates a load of unnecessary assembler instructions if another as the first variable is accessed.
       mov     r2,#0x00
       mov     r3,#0xF0
       mov     dpl,r2
       mov     dph,r3
       inc     dptr
       mov     a,#0x04
       movx    @dptr,a
instead of
       mov     dptr,#0xF001
       mov     a,#0x03
       movx    @dptr,a

Please see the attached test file.

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>Comment By: Maarten Brock (maartenbrock)
Date: 2008-02-01 13:02

Message:
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Apparently the result differs whether the struct is volatile or not. But
this is not a result of the peephole optimizer. Rather the '+' operator is
not optimized in the ast.

This is no bug, because the generated code works perfectly though
suboptimal. Therefor I move this to the feature requests.

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Comment By: Johann Glaser (hansiglaser)
Date: 2007-12-28 20:56

Message:
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Originator: NO

Oops, forgot to login before submitting the bug.

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