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This is to allow for making the stack bigger for
anything that needs to change the size of it.
- Made the SuB Suite set the stack pointer to the end
of the usable RAM, and allow for changing the stack
size.
In this case, the size of the stack is currently set
to 192K, with the end of the heap being just below
the stack.
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emulator's memory.
All reads outside of the emulator's memory give back
$/0xFF bytes, while all writes outside of the
emulator's memory are ignored.
- Implemented malloc(), and free() in the SuB Suite.
In order to do this, I had to add support for a heap,
which I did by reserving the first 3 banks of the
address space (the first 192K), and by adding a
routine that finds the end of the RAM.
In this case, I set the starting address for the
routine at bank 3 (bank 4 with one indexing), but,
the routine's starting address isn't hardcoded, and
thus, any starting address can be passed as an
argument.
The routine uses the fact that we can now read/write
outside the emulator's memory, and also uses the
fact that writing outside the emulator's memory will
be ignored, and that reading outside the emulator's
memory will always read $/0xFF bytes, and uses that
to signal that it's reached the end of the RAM.
- Added a test program for getting the size of RAM
starting at address $/0x20000.
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- Added a memcopy() function, for later on.
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- Optimized the memory read, and write functions.
- Made the emulator faster, and cleaner in general.
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- Simplified the effective address functions.
- Made SuBEditor a bit faster.
- JSR, and RTS now support using the RS prefix, which
is used to specify the return address size, with an
RS prefix of 0 being a return address size of 64
bits, rather than 8 bits.
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address handling.
It's now all done using several functions for each
addressing mode, with the result being the effective
address.
I did this to make the codebase cleaner, and more
readable.
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It now uses a struct to store the escape sequence.
Before it handles the escape sequence, it parses it,
which includes things like getting any arguments
that are supplied, and getting the mode type.
- Moved the code that handles control codes to a
separate function.
The reason for doing this was because I wanted to make
the escape sequence handling faster, but also make the
code more readable at the same time.
I got the idea to do this from st, a terminal emulator
created by the suckless.org project.
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instruction formatting simpler.
- Refactored the instruction table of the emulator's
assembler, it now has two parts, the addressing mode
bits, and the base value.
The base value is what's used to generate the actual
opcode, with the addressing mode bits telling the
assembler what addressing modes this instruction
supports.
The reason for doing this was to use less space. For
comparison, the previous version used 870 bytes for
the instruction table, while the new version uses
only 222 bytes. The new version is nearly 4 times
smaller than the pervious version.
- The B register based ALU instructions now use their
own addressing mode, and are specified by using 'b'
as the operand for those instructions.
For example, to add the Accumulator with the B
register, you now use "ADC B" instead of "AAB".
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- Changed the file structure of the SuB Suite, so that
all variable declarations, symbols, and constants
are in a single file.
- Moved the C library functionss into a separate
file, and made them use stack frames.
- Added support for using the emulator's assembler for
realtime debugging, to enter it, get in to stepping
mode by pressing Ctrl+s, press any other key, then
press F1,
The reason for having to press some other key before
pressing F1 is because it only allows entering the
assembler when the keyboard is not ready.
- Added the ".res" directive to the emulator's
assembler, the ".res" directive tells the assembler
to reserve however many bytes specified by the
operand.
- Fixed some bugs in the emulator's assembler.
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- Added a new preifx called the OF prefix, which adds
the contents of a specific register to the current
operand.
- Added a table generator, which parses opcode table
csv files.
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- Fixed some bugs in the emulator's assembler.
- Worked on SuBAsm's lexer some more.
- Created a new directory for the SuB suite, and moved
all of the SuB suite's files in there.
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all the value getting, and setting into macros.
This is to make the codebase cleaner.
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The reason for doing this was because JSL, and RTL are
redundent, as they both do the same thing as JSR, and
RTS.
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support for comma separated values.
The assembler now uses a linked list of tokenized
lines, each containing a linked list of tokens for
that line.
I also moved all of the large tables into the higher
parts of memory, in order to free up the lower part of
memory for the user.
Comma sepparated values only work with directives, and
only with the byte", word, dword, and qword directives.
I also added support for getting the upper, and lower
halves of an address. The tokens for both of those are
'<', and '>' respectively.
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functions.
I did this to make it more readable, while still
making it fast, due to inlining it.
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