bslathi19/cc65
1
0
Fork 0
Code Issues Pull Requests Actions 1 Packages Projects Releases Wiki Activity

versionable header for sim65

Browse Source 
load and run address now configured from header
fix error codes not to conflict with test
fix test/misc/endless.c which is supposed to fail if an endless loop does not occur
This commit is contained in:
bbbradsmith
2019-05-29 16:04:54 -04:00
committed by Oliver Schmidt
parent 07ca772932
commit fb7d4acd5c
12 changed files with 129 additions and 39 deletions
Download Patch File Download Diff File Expand all files Collapse all files

29
doc/sim65.sgml
View File

@@ -140,28 +140,39 @@ Assembly tests may similarly be assembled and linked with
and the sim65 library provides an <tt/exit/ symbol that the program may <tt/JMP/
to terminate with the current A register value as an exit code.
Without using the provided target library, there are some relevant internal details:
The binary file has a 12 byte header:
<itemize>
<item>The binary input file has a 2 byte header. The first byte indicates CPU type:
0 = 6502, 1 = 65C02. The second byte is the address of the C parameter stack pointer
<tt/sp/, used by the paravirtualization functions.
<item>5 byte **signature**: <tt/$73, $69, $6D, $36, $35/ or <tt/'sim65'/
<item>The rest of the input file, after the header, will be loaded at <tt/$0200/,
and execution will begin at <tt/$0200/.
<item>1 byte **version**: <tt/2/
<item>1 byte **CPU type**: <tt/0/ = 6502, <tt/1/ = 65C02
<item>1 byte **sp address**: the zero page address of the C parameter stack pointer <tt/sp/ used by the paravirtualization functions
<item>1 word **load address**: where to load the data from the file into memory (default: <tt/$0200/)
<item>1 word **reset address**: specifies where to begin execution after loading (default: <tt/$0200/)
</itemize>
Other internal details:
<itemize>
<item>The entire 64 kilobyte address space is writeable RAM.
Aside from the loaded binary, the reset vector at <tt/$FFFC/ will be
pre-loaded with <tt/$0200/ as the start address.
pre-loaded with the given **reset address**.
<item>The <tt/exit/ address is <tt/$FFF1/.
Jumping to this address will terminate execution with the A register value as an exit code.
<item>The built-in functions are provided by 6 paravirtualization hooks present at
<tt/$FFF0-$FFF5/. Except for <tt/exit/, a <tt/JSR/ to one of these
addresses will return immediately after performing a special function,
intended for use with the sim65 target C library.
addresses will return immediately after performing a special function.
These use cc65 calling conventions, and are intended for use with the sim65 target C library.
<item><tt/IRQ/ and <tt/NMI/ events will not be generated, though <tt/BRK/
can be used if the IRQ vector at <tt/$FFFE/ is manually prepared by the test code.