the10thwiz/cc65
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Adapted, to the c64 target, the INIT-segment overlay scheme from the apple2 targets.

Browse Source 
When a program starts running, INIT is moved from one place to another place.  Then, INIT's code is executed; and, the first place is re-used for variables.  After the INIT code has finished, the second place can be re-used by the heap and the C stack.  That means that initiation code and data won't waste any RAM space after they stop being needed.
This commit is contained in:
Greg King
2015-10-05 05:47:43 -04:00
parent 24c2da980b
commit 074e10d288
5 changed files with 200 additions and 104 deletions
Download Patch File Download Diff File Expand all files Collapse all files

35
cfg/c64.cfg
View File

@@ -1,26 +1,31 @@
FEATURES {
STARTADDRESS: default = $0801;
}
SYMBOLS {
__LOADADDR__: type = import;
__EXEHDR__: type = import;
__STACKSIZE__: type = weak, value = $0800; # 2k stack
__HIMEM__: type = weak, value = $D000;
}
MEMORY {
ZP: file = "", define = yes, start = $0002, size = $001A;
LOADADDR: file = %O, start = $07FF, size = $0002;
HEADER: file = %O, start = $0801, size = $000C;
RAM: file = %O, define = yes, start = $080D, size = $C7F3 - __STACKSIZE__;
ZP: file = "", define = yes, start = $0002, size = $001A;
LOADADDR: file = %O, start = %S - 2, size = $0002;
HEADER: file = %O, define = yes, start = %S, size = $000D;
RAM: file = %O, start = __HEADER_LAST__, size = __HIMEM__ - __STACKSIZE__ - __HEADER_LAST__;
MOVE: file = %O, start = __ZPSAVE_LOAD__, size = __HIMEM__ - __INIT_RUN__;
}
SEGMENTS {
LOADADDR: load = LOADADDR, type = ro;
EXEHDR: load = HEADER, type = ro;
STARTUP: load = RAM, type = ro;
LOWCODE: load = RAM, type = ro, optional = yes;
INIT: load = RAM, type = ro, define = yes, optional = yes;
CODE: load = RAM, type = ro;
RODATA: load = RAM, type = ro;
DATA: load = RAM, type = rw;
ZPSAVE: load = RAM, type = bss;
BSS: load = RAM, type = bss, define = yes;
ZEROPAGE: load = ZP, type = zp;
ZEROPAGE: load = ZP, type = zp;
LOADADDR: load = LOADADDR, type = ro;
EXEHDR: load = HEADER, type = ro;
STARTUP: load = RAM, type = ro;
LOWCODE: load = RAM, type = ro, optional = yes;
CODE: load = RAM, type = ro;
RODATA: load = RAM, type = ro;
DATA: load = RAM, type = rw;
ZPSAVE: load = RAM, type = bss, define = yes;
BSS: load = RAM, type = bss, define = yes;
INIT: load = MOVE, run = RAM, type = ro, define = yes, optional = yes;
}
FEATURES {
CONDES: type = constructor,