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(sccz80) Support struct assignment #1132

Closed
5 of 6 tasks
suborb opened this issue Apr 14, 2019 · 1 comment
Closed
5 of 6 tasks

(sccz80) Support struct assignment #1132

suborb opened this issue Apr 14, 2019 · 1 comment
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enhancement sccz80
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z88dk 2.0

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@suborb
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suborb commented Apr 14, 2019 •
edited

Now that sdcc supports assigning structs, sccz80 should be updated so that source code compatibility is maintained.

  • Assignment of locals
  • Assignment of globals
  • Passing structs to functions
  • Passing structs to __far functions
  • Passing structs to function pointers
  • Returning structs from function

The first two should be relatively trivial, passing structs shouldn't be too difficult.

Returning structs is slightly trickier, several ways to do it:

  1. Reserve space on the stack prior to the call and then return places the struct in reserved space (needs functions prototyped, how would this work with far calls which have a different stack?)
  2. The function manipulates the stack pointer on return and creates the space (awkward for variadic functions)
  3. Use a static buffer (re-entrancy issues)

It feels like 1. is the way to go, but will need coordination with sdcc so the ABI is the same.
suborb added a commit that referenced this issue Apr 14, 2019
@suborb
Issue #1132: Assignment of structs supported.
1e3465e 
__far access warns
suborb added a commit that referenced this issue Apr 14, 2019
@suborb
Issue #1132: Struct assignment
a2aff30 
Bit of (non-verified) work on passing parameters + bitfields
suborb added a commit that referenced this issue Apr 14, 2019
@suborb
Issue #1132: Test for passing a struct as a parameter.
8751dfe 
This may well break existing code...
suborb added a commit that referenced this issue Apr 14, 2019
@suborb
Issue #1132: The array may be defined, but empty, so check
f80bed2
@suborb suborb mentioned this issue Apr 14, 2019
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suborb added a commit that referenced this issue Apr 14, 2019
@suborb
Issue #1132: Passing structs to function pointers
1e79ec0
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suborb commented Apr 15, 2019

This was merged as #1134 - all apart from returning structs from functions which I'l leave for a while.

@suborb suborb closed this as completed Apr 15, 2019
@suborb suborb added this to Todo in z88dk 2.0 via automation May 5, 2019
@suborb suborb moved this from Todo to Done in z88dk 2.0 May 5, 2019
@patacongo patacongo mentioned this issue Mar 24, 2020
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patacongo pushed a commit to patacongo/nuttx that referenced this issue Apr 11, 2020
@gregory-nutt
Remove CONFIG_CAN_PASS_STRUCT
879d496 
This commit resolves issue apache#620:

Remove CONFIG_CAN_PASS_STRUCTS apache#620

The configuration option CONFIG_CAN_PASS_STRUCTS was added many years ago to support an old version of the SDCC compiler. That compiler is currently used only with the Z80 and Z180 targets. The limitation of that old compiler was that it could not pass structures or unions as either inputs or outputs. For example:

    #ifdef CONFIG_CAN_PASS_STRUCTS
    struct mallinfo mallinfo(void);
    #else
    int      mallinfo(FAR struct mallinfo *info);
    #endif

And even leads to violation of a few POSIX interfaces like:

    #ifdef CONFIG_CAN_PASS_STRUCTS
    int  sigqueue(int pid, int signo, union sigval value);
    #else
    int  sigqueue(int pid, int signo, FAR void *sival_ptr);
    #endif

This breaks the 1st INVIOLABLES rule:

Strict POSIX compliance
-----------------------

  o Strict conformance to the portable standard OS interface as defined at
    OpenGroup.org.
  o A deeply embedded system requires some special support.  Special
    support must be minimized.
  o The portable interface must never be compromised only for the sake of
    expediency.
  o Expediency or even improved performance are not justifications for
   violation of the strict POSIX interface

Also, it appears that the current SDCC compilers have resolve this issue and so, perhaps, this is no longer a problem: z88dk/z88dk#1132

NOTE:  This commit cannot pass the PR checks because it depends on matching changes to the apps/ directory.
@patacongo patacongo mentioned this issue Apr 11, 2020
Merged
Ouss4 pushed a commit to apache/nuttx that referenced this issue Apr 11, 2020
@gregory-nutt @Ouss4
Remove CONFIG_CAN_PASS_STRUCT
67ec3d7 
This commit resolves issue #620:

Remove CONFIG_CAN_PASS_STRUCTS #620

The configuration option CONFIG_CAN_PASS_STRUCTS was added many years ago to support an old version of the SDCC compiler. That compiler is currently used only with the Z80 and Z180 targets. The limitation of that old compiler was that it could not pass structures or unions as either inputs or outputs. For example:

    #ifdef CONFIG_CAN_PASS_STRUCTS
    struct mallinfo mallinfo(void);
    #else
    int      mallinfo(FAR struct mallinfo *info);
    #endif

And even leads to violation of a few POSIX interfaces like:

    #ifdef CONFIG_CAN_PASS_STRUCTS
    int  sigqueue(int pid, int signo, union sigval value);
    #else
    int  sigqueue(int pid, int signo, FAR void *sival_ptr);
    #endif

This breaks the 1st INVIOLABLES rule:

Strict POSIX compliance
-----------------------

  o Strict conformance to the portable standard OS interface as defined at
    OpenGroup.org.
  o A deeply embedded system requires some special support.  Special
    support must be minimized.
  o The portable interface must never be compromised only for the sake of
    expediency.
  o Expediency or even improved performance are not justifications for
   violation of the strict POSIX interface

Also, it appears that the current SDCC compilers have resolve this issue and so, perhaps, this is no longer a problem: z88dk/z88dk#1132

NOTE:  This commit cannot pass the PR checks because it depends on matching changes to the apps/ directory.
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