diff --git a/asminc/c64.inc b/asminc/c64.inc
index 5815bebf9..ababb1ea0 100644
--- a/asminc/c64.inc
+++ b/asminc/c64.inc
@@ -24,6 +24,7 @@ SCREEN_PTR := $D1 ; Pointer to current char in text screen
CURS_X := $D3 ; Cursor column
CURS_Y := $D6 ; Cursor row
CRAM_PTR := $F3 ; Pointer to current char in color RAM
+FREKZP := $FB ; Five unused bytes
BASIC_BUF := $200 ; Location of command-line
BASIC_BUF_LEN = 89 ; Maximum length of command-line
@@ -212,4 +213,3 @@ CASSMOT = $20 ; Cassette motor on
TP_FAST = $80 ; Switch Rossmoeller TurboProcess to fast mode
RAMONLY = $F8 ; (~(LORAM | HIRAM | IOEN)) & $FF
-
diff --git a/cfg/c64-overlay.cfg b/cfg/c64-overlay.cfg
index 2f7693e6e..07ce9e4b6 100644
--- a/cfg/c64-overlay.cfg
+++ b/cfg/c64-overlay.cfg
@@ -1,64 +1,70 @@
+FEATURES {
+ STARTADDRESS: default = $0801;
+}
SYMBOLS {
- __LOADADDR__: type = import;
- __EXEHDR__: type = import;
- __OVERLAYADDR__: type = import;
- __STACKSIZE__: type = weak, value = $0800; # 2k stack
- __OVERLAYSIZE__: type = weak, value = $1000; # 4k overlay
+ __LOADADDR__: type = import;
+ __EXEHDR__: type = import;
+ __OVERLAYADDR__: type = import;
+ __STACKSIZE__: type = weak, value = $0800; # 2k stack
+ __OVERLAYSIZE__: type = weak, value = $1000; # 4k overlay
+ __HIMEM__: type = weak, value = $D000;
+ __OVERLAYSTART__: type = export, value = __HIMEM__ - __OVERLAYSIZE__;
}
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 - __OVERLAYSIZE__ - __STACKSIZE__;
- OVL1ADDR: file = "%O.1", start = $CFFE - __OVERLAYSIZE__, size = $0002;
- OVL1: file = "%O.1", start = $D000 - __OVERLAYSIZE__, size = __OVERLAYSIZE__;
- OVL2ADDR: file = "%O.2", start = $CFFE - __OVERLAYSIZE__, size = $0002;
- OVL2: file = "%O.2", start = $D000 - __OVERLAYSIZE__, size = __OVERLAYSIZE__;
- OVL3ADDR: file = "%O.3", start = $CFFE - __OVERLAYSIZE__, size = $0002;
- OVL3: file = "%O.3", start = $D000 - __OVERLAYSIZE__, size = __OVERLAYSIZE__;
- OVL4ADDR: file = "%O.4", start = $CFFE - __OVERLAYSIZE__, size = $0002;
- OVL4: file = "%O.4", start = $D000 - __OVERLAYSIZE__, size = __OVERLAYSIZE__;
- OVL5ADDR: file = "%O.5", start = $CFFE - __OVERLAYSIZE__, size = $0002;
- OVL5: file = "%O.5", start = $D000 - __OVERLAYSIZE__, size = __OVERLAYSIZE__;
- OVL6ADDR: file = "%O.6", start = $CFFE - __OVERLAYSIZE__, size = $0002;
- OVL6: file = "%O.6", start = $D000 - __OVERLAYSIZE__, size = __OVERLAYSIZE__;
- OVL7ADDR: file = "%O.7", start = $CFFE - __OVERLAYSIZE__, size = $0002;
- OVL7: file = "%O.7", start = $D000 - __OVERLAYSIZE__, size = __OVERLAYSIZE__;
- OVL8ADDR: file = "%O.8", start = $CFFE - __OVERLAYSIZE__, size = $0002;
- OVL8: file = "%O.8", start = $D000 - __OVERLAYSIZE__, size = __OVERLAYSIZE__;
- OVL9ADDR: file = "%O.9", start = $CFFE - __OVERLAYSIZE__, size = $0002;
- OVL9: file = "%O.9", start = $D000 - __OVERLAYSIZE__, size = __OVERLAYSIZE__;
+ 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, define = yes, start = __HEADER_LAST__, size = __OVERLAYSTART__ - __STACKSIZE__ - __HEADER_LAST__;
+ MOVE: file = %O, start = __ZPSAVE_LOAD__, size = __HIMEM__ - __INIT_RUN__;
+ OVL1ADDR: file = "%O.1", start = __OVERLAYSTART__ - 2, size = $0002;
+ OVL1: file = "%O.1", start = __OVERLAYSTART__, size = __OVERLAYSIZE__;
+ OVL2ADDR: file = "%O.2", start = __OVERLAYSTART__ - 2, size = $0002;
+ OVL2: file = "%O.2", start = __OVERLAYSTART__, size = __OVERLAYSIZE__;
+ OVL3ADDR: file = "%O.3", start = __OVERLAYSTART__ - 2, size = $0002;
+ OVL3: file = "%O.3", start = __OVERLAYSTART__, size = __OVERLAYSIZE__;
+ OVL4ADDR: file = "%O.4", start = __OVERLAYSTART__ - 2, size = $0002;
+ OVL4: file = "%O.4", start = __OVERLAYSTART__, size = __OVERLAYSIZE__;
+ OVL5ADDR: file = "%O.5", start = __OVERLAYSTART__ - 2, size = $0002;
+ OVL5: file = "%O.5", start = __OVERLAYSTART__, size = __OVERLAYSIZE__;
+ OVL6ADDR: file = "%O.6", start = __OVERLAYSTART__ - 2, size = $0002;
+ OVL6: file = "%O.6", start = __OVERLAYSTART__, size = __OVERLAYSIZE__;
+ OVL7ADDR: file = "%O.7", start = __OVERLAYSTART__ - 2, size = $0002;
+ OVL7: file = "%O.7", start = __OVERLAYSTART__, size = __OVERLAYSIZE__;
+ OVL8ADDR: file = "%O.8", start = __OVERLAYSTART__ - 2, size = $0002;
+ OVL8: file = "%O.8", start = __OVERLAYSTART__, size = __OVERLAYSIZE__;
+ OVL9ADDR: file = "%O.9", start = __OVERLAYSTART__ - 2, size = $0002;
+ OVL9: file = "%O.9", start = __OVERLAYSTART__, size = __OVERLAYSIZE__;
}
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;
- OVL1ADDR: load = OVL1ADDR, type = ro;
- OVERLAY1: load = OVL1, type = ro, define = yes, optional = yes;
- OVL2ADDR: load = OVL2ADDR, type = ro;
- OVERLAY2: load = OVL2, type = ro, define = yes, optional = yes;
- OVL3ADDR: load = OVL3ADDR, type = ro;
- OVERLAY3: load = OVL3, type = ro, define = yes, optional = yes;
- OVL4ADDR: load = OVL4ADDR, type = ro;
- OVERLAY4: load = OVL4, type = ro, define = yes, optional = yes;
- OVL5ADDR: load = OVL5ADDR, type = ro;
- OVERLAY5: load = OVL5, type = ro, define = yes, optional = yes;
- OVL6ADDR: load = OVL6ADDR, type = ro;
- OVERLAY6: load = OVL6, type = ro, define = yes, optional = yes;
- OVL7ADDR: load = OVL7ADDR, type = ro;
- OVERLAY7: load = OVL7, type = ro, define = yes, optional = yes;
- OVL8ADDR: load = OVL8ADDR, type = ro;
- OVERLAY8: load = OVL8, type = ro, define = yes, optional = yes;
- OVL9ADDR: load = OVL9ADDR, type = ro;
- OVERLAY9: load = OVL9, type = ro, define = yes, optional = yes;
+ 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;
+ OVL1ADDR: load = OVL1ADDR, type = ro;
+ OVERLAY1: load = OVL1, type = ro, define = yes, optional = yes;
+ OVL2ADDR: load = OVL2ADDR, type = ro;
+ OVERLAY2: load = OVL2, type = ro, define = yes, optional = yes;
+ OVL3ADDR: load = OVL3ADDR, type = ro;
+ OVERLAY3: load = OVL3, type = ro, define = yes, optional = yes;
+ OVL4ADDR: load = OVL4ADDR, type = ro;
+ OVERLAY4: load = OVL4, type = ro, define = yes, optional = yes;
+ OVL5ADDR: load = OVL5ADDR, type = ro;
+ OVERLAY5: load = OVL5, type = ro, define = yes, optional = yes;
+ OVL6ADDR: load = OVL6ADDR, type = ro;
+ OVERLAY6: load = OVL6, type = ro, define = yes, optional = yes;
+ OVL7ADDR: load = OVL7ADDR, type = ro;
+ OVERLAY7: load = OVL7, type = ro, define = yes, optional = yes;
+ OVL8ADDR: load = OVL8ADDR, type = ro;
+ OVERLAY8: load = OVL8, type = ro, define = yes, optional = yes;
+ OVL9ADDR: load = OVL9ADDR, type = ro;
+ OVERLAY9: load = OVL9, type = ro, define = yes, optional = yes;
}
FEATURES {
CONDES: type = constructor,
diff --git a/cfg/c64.cfg b/cfg/c64.cfg
index 5d8befd02..8fe1c0c6f 100644
--- a/cfg/c64.cfg
+++ b/cfg/c64.cfg
@@ -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, define = yes, 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;
}
FEATURES {
CONDES: type = constructor,
diff --git a/libsrc/c64/crt0.s b/libsrc/c64/crt0.s
index 24fe4376b..a2abe91af 100644
--- a/libsrc/c64/crt0.s
+++ b/libsrc/c64/crt0.s
@@ -4,12 +4,12 @@
.export _exit
.export __STARTUP__ : absolute = 1 ; Mark as startup
+
.import initlib, donelib
- .import zerobss
- .import callmain
- .import RESTOR, BSOUT, CLRCH
+ .import moveinit, zerobss, callmain
+ .import BSOUT
.import __RAM_START__, __RAM_SIZE__ ; Linker generated
- .import __STACKSIZE__ ; Linker generated
+ .import __STACKSIZE__ ; from configure file
.importzp ST
.include "zeropage.inc"
@@ -23,14 +23,6 @@
Start:
-; Save the zero-page locations that we need.
-
- ldx #zpspace-1
-L1: lda sp,x
- sta zpsave,x
- dex
- bpl L1
-
; Switch to the second charset.
lda #14
@@ -39,35 +31,30 @@ L1: lda sp,x
; Switch off the BASIC ROM.
lda $01
- pha ; Remember the value
+ sta mmusave ; Save the memory configuration
and #$F8
ora #$06 ; Enable Kernal+I/O, disable BASIC
sta $01
-; Clear the BSS data.
-
- jsr zerobss
-
-; Save some system settings; and, set up the stack.
-
- pla
- sta mmusave ; Save the memory configuration
-
tsx
stx spsave ; Save the system stack ptr
- lda #<(__RAM_START__ + __RAM_SIZE__ + __STACKSIZE__)
- sta sp
- lda #>(__RAM_START__ + __RAM_SIZE__ + __STACKSIZE__)
- sta sp+1 ; Set argument stack ptr
+; Allow some re-entrancy by skipping the next task if it already was done.
+; This sometimes can let us rerun the program without reloading it.
-; Call the module constructors.
+ ldx move_init
+ beq L0
- jsr initlib
+; Move the INIT segment from where it was loaded (over ZPSAVE and BSS)
+; into where it must be run (in the heap).
-; Push the command-line arguments; and, call main().
+ jsr moveinit
+ dec move_init ; set to false
- jsr callmain
+; Save space by putting the rest of the start-up code in the INIT segment,
+; which can be re-used by the heap and the C stack.
+
+L0: jsr initstart
; Back from main() [this is also the exit() entry]. Run the module destructors.
@@ -98,14 +85,55 @@ L2: lda zpsave,x
rts
+
+; ------------------------------------------------------------------------
+
+.segment "INIT"
+
+initstart:
+
+; Save the zero-page locations that we need.
+
+ ldx #zpspace-1
+L1: lda sp,x
+ sta zpsave,x
+ dex
+ bpl L1
+
+; Clear the BSS data.
+
+ jsr zerobss
+
+; Set up the stack.
+
+ lda #<(__RAM_START__ + __RAM_SIZE__ + __STACKSIZE__)
+ ldx #>(__RAM_START__ + __RAM_SIZE__ + __STACKSIZE__)
+ sta sp
+ stx sp+1 ; Set argument stack ptr
+
+; Call the module constructors.
+
+ jsr initlib
+
+; Push the command-line arguments; and, call main().
+
+ jmp callmain
+
+
; ------------------------------------------------------------------------
; Data
+.data
+
+; These two variables were moved out of the BSS segment, and into DATA, because
+; we need to use them before INIT is moved off of BSS, and before BSS is zeroed.
+
+mmusave:.res 1
+spsave: .res 1
+
+move_init:
+ .byte 1
+
.segment "ZPSAVE"
zpsave: .res zpspace
-
-.bss
-
-spsave: .res 1
-mmusave:.res 1
diff --git a/libsrc/common/moveinit.s b/libsrc/common/moveinit.s
new file mode 100644
index 000000000..2186adf0e
--- /dev/null
+++ b/libsrc/common/moveinit.s
@@ -0,0 +1,45 @@
+;
+; 2015-10-07, Greg King
+;
+
+ .export moveinit
+
+ .import __INIT_LOAD__, __INIT_RUN__, __INIT_SIZE__ ; Linker-generated
+
+ .macpack cpu
+ .macpack generic
+
+
+; Put this in the DATA segment because it is self-modifying code.
+
+.data
+
+; Move the INIT segment from where it was loaded (over the bss segments)
+; into where it must be run (in the heap). The two areas might overlap; and,
+; the segment is moved upwards. Therefore, this code starts at the highest
+; address, and decrements to the lowest address. The low bytes of the starting
+; pointers are not sums. The high bytes are sums; but, they do not include the
+; carry. Both the low-byte sums and the carries will be done when the pointers
+; are indexed by the .Y register.
+
+moveinit:
+
+; First, move the last, partial page.
+; Then, move all of the full pages.
+
+ ldy #<__INIT_SIZE__ ; size of partial page
+ ldx #>__INIT_SIZE__ + (<__INIT_SIZE__ <> 0) ; number of pages, including partial
+
+L1: dey
+init_load:
+ lda __INIT_LOAD__ + (__INIT_SIZE__ & $FF00) - $0100 * (<__INIT_SIZE__ = 0),y
+init_run:
+ sta __INIT_RUN__ + (__INIT_SIZE__ & $FF00) - $0100 * (<__INIT_SIZE__ = 0),y
+ tya
+ bnz L1 ; page not finished
+
+ dec init_load+2
+ dec init_run+2
+ dex
+ bnz L1 ; move next page
+ rts