The goal was to improve readability, but along the way a few things were
gained.
- Sorted sym and map files
- Infrastructure for supporting multiple .o versions
- Valgrind-proof, as far as my testing goes anyways
- Improved verbosity messages
- Added error checking
- Performance improvements, see end of commit message
The readability improvement was spurred while trying to make sense of the
old code while trying to implement features such as sorted sym and map
files.
I also did my best to remove hardcoded logic, such that modifications
should be doable; for example, "RAM loading" sections, which are linked
against a different location than the one they're stored at.
Some work remains to be done, see the "TODO:" and "FIXME:" comments.
Further, while regression tests pass, this new linker should be tested on
different codebases (ideally while instrumented with `make develop` and
under valgrind).
The few errors spotted in the man pages (alignment) need to be corrected.
Finally, documentation comments need to be written, I have written a lot of
them but not all.
This also provides a significant performance boost (benchmarked with a
51994-symbol project):
Current master RGBLINK:
2.02user 0.03system 0:02.06elapsed 99%CPU (0avgtext+0avgdata 84336maxresident)k
0inputs+11584outputs (0major+20729minor)pagefaults 0swaps
Rewritten RGBLINK:
0.19user 0.06system 0:00.63elapsed 40%CPU (0avgtext+0avgdata 32460maxresident)k
23784inputs+11576outputs (0major+7672minor)pagefaults 0swaps
Some errors are only tripped in `out_WriteObject`, which was
basically a stub when `-o` wasn't specified. Now, instead,
errors are checked in a separate function before out_WriteFile
This adds two new directives: newcharmap and setcharmap.
newcharmap creates a new charmap and switches to it.
setcharmap switches to an existing charmap.
When trying to fix a section becoming too large, the size it reached is necessary to know whether to optimize away a few bytes or split it entirely.
This error is also commonly encountered when INCBINing too large a slice of a file, in which case the amount of bytes by which the section is too large is again an useful information
Previously, a PUSHS before a SECTION directive would cause rgbasm to crash when encountering a subsequent POPS.
This is because the subsequently-called out_setCurrentSection() expected the new section to be non-null, which wasn’t the case in this situation. This has been addressed by allowing the ‘null’ section to be set in this function, and only dereferencing it (to set nPC) if a non-null section is to be set.
In practice, this means that PUSHS/POPS can now be used to push/restore a context without a section.
The createpatch() function was using a fixed-size buffer. I've changed it
to be dynamically allocated. I saw that the RPN format used in patches is
slightly different from the one used internally in the assembler, so I
added a new member to the Expression struct to track the patch size.
I've also limited the RPN expression length to 1MB. I realized that the
patch RPN expression could potentially be longer than the internal RPN
expression, so the internal expression would need a limit smaller than
UINT32_MAX. I thought 1MB would be a reasonable limit.
Previously, JR was only allowed to labels (in the same section, or
different sections). When trying to JR to an address specified as a
numeric value, rgbasm would fail to calculate the JR offset (as it
doesn't know the final address of the JR so it can't calculate the
difference).
This patch makes rgblink calculate the offset whenever there is a JR.
Signed-off-by: Antonio Niño Díaz <antonio_nd@outlook.com>
Previously, JR was only allowed if the destination label was in the same
section as the JR. This patch removes this restriction. The check to see
if the relative value overflows is now done when linking the ROM.
Signed-off-by: Antonio Niño Díaz <antonio_nd@outlook.com>
With permission from the main authors [1], most of the code has been
relicensed under the MIT license.
SPDX license identifiers are used so that the license headers in source
code files aren't too large.
Add CONTRIBUTORS.rst file.
[1] https://github.com/rednex/rgbds/issues/128
Signed-off-by: Antonio Niño Díaz <antonio_nd@outlook.com>
NULL error messages have been given a description.
Messages that weren't descriptive enough now also print the name of the
function that has failed.
Signed-off-by: Antonio Niño Díaz <antonio_nd@outlook.com>
Now, when POPS is executed, it restores the symbol scope of the
corresponding PUSHS. That way, the local symbols previously available
can be used again after the POPS.
This is useful in cases like this one:
```
SECTION "Section 1", ROMX
BigFunction:
...
.loop:
...
PUSHS
SECTION "Section 2", ROMX
DataForBigFunction:
DB 1, 2, 3, 4, 5
POPS
ld a,BANK(DataForBigFunction)
ld hl,DataForBigFunction
...
jr .loop
```
Signed-off-by: Antonio Niño Díaz <antonio_nd@outlook.com>
The bank of a section can be requested with `BANK("Section Name")`, and
the bank of the current section with `BANK(@)`. In both cases, the bank
number is resolved by the linker.
New commands have been added to the list of RPN commands of object
files, and the rest has been moved so that new additions don't force a
new change in the number of the enumerations.
Increase object file version, as it is now incompatible with the old
format.
Update manpages to reflect the new ways of using `BANK()` and the new
format of the object files.
Signed-off-by: Antonio Niño Díaz <antonio_nd@outlook.com>
Not all occurrences have been replaced, in some cases they have been
left as they were before (like in rgbgfx and when they are in the
interface of a C standard library function).
Signed-off-by: Antonio Niño Díaz <antonio_nd@outlook.com>
The previous change has broken compatibility of object files, so it is
needed to increment the version number to make the linker reject files
generated with the old code.
Signed-off-by: Antonio Niño Díaz <antonio_nd@outlook.com>
Unions allow multiple memory allocations (using ds, etc.) to share the
same space in memory.
This allows games to use the same memory for different purposes,
depending on their state.
This also adds documentation on how to use the new UNION, NEXTU, and
ENDU keywords.
Local symbols can now be referenced outside the scope of their parent, by using the syntax “Parent.Chlid”.
- Local symbol names are now stored internally as “Parent.Child”.
- The symbol’s scope field no longer forms a linked list of the prior local symbols; it will now always contain the parent.
- Add the ability use EXPORT and GLOBAL with local symbols.
- Reduce duplication between findsymbol() and findpsymbol(), as well as between sym_AddLocalReloc() and sym_AddReloc().
There are two ways in which the assembly process can fail:
1. If there is a really big problem that compromises the whole process,
the assembler has to stop right there and generate an error message.
This happens with unterminated REPT loops, macros, etc.
2. If the problem isn't that big and the process can still continue,
even though the final result is invalid, the assembler can try to
continue and warn the user about all errors it finds in the code.
This patch clarifies the use of each function and replaces the function
used in two places by the correct one.
Signed-off-by: Antonio Niño Díaz <antonio_nd@outlook.com>
When allocating a section, allocate only the max possible size for that
type (only applies to ROM0 and ROMX).
When finding an overflow, in any kind of section, output an error with
the location of the line of code that caused the overflow.
Signed-off-by: Antonio Niño Díaz <antonio_nd@outlook.com>
Instead of allocating 0x4000 bytes for all sections and resize them as
needed, allocate 0x8000 bytes and don't let them to be resized. This is
the max possible size (ROM0 when ROMX sections aren't present).
Buffers are not needed for RAM sections, this patch changes the code so
that it only allocates buffers for ROM sections.
Signed-off-by: Antonio Niño Díaz <antonio_nd@outlook.com>
Aligned sections can now be created with out_NewAlignedSection(). This information is stored in created object files, and read by the linker.
The names of each section are also included in the object file, enabling potential improvements to error messages in the future.
Fixed as follows: if the symbol doesn't exist, don't add it to the relocation
table. The functions calling createpatch will nevertheless increment PC
correctly.
Test case:
SECTION "CODE", CODE
glob:
jp .loc
; from test/asm/banknoexist.asm:
SECTION "sec", ROM0
db BANK(noexist)
See also issue #68
