From 074e10d28877647862d2dc94c2a8ce93e07585a1 Mon Sep 17 00:00:00 2001 From: Greg King Date: Mon, 5 Oct 2015 05:47:43 -0400 Subject: [PATCH] Adapted, to the c64 target, the INIT-segment overlay scheme from the apple2 targets. 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. --- asminc/c64.inc | 2 +- cfg/c64-overlay.cfg | 112 +++++++++++++++++++++------------------ cfg/c64.cfg | 35 ++++++------ libsrc/c64/crt0.s | 101 +++++++++++++++++++++++------------ libsrc/common/moveinit.s | 54 +++++++++++++++++++ 5 files changed, 200 insertions(+), 104 deletions(-) create mode 100644 libsrc/common/moveinit.s 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..58612e18e 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 + __STACKSIZE__: type = weak, value = $0800; # 2k stack + __OVERLAYSIZE__: type = weak, value = $1000; # 4k overlay + __HIMEM__: type = weak, value = $D000; + __HIMEM2__: type = export, value = __HIMEM__ - 2; } 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, start = __HEADER_LAST__, size = __HIMEM__ - __OVERLAYSIZE__ - __STACKSIZE__ - __HEADER_LAST__; + MOVE: file = %O, start = __ZPSAVE_LOAD__, size = __HIMEM__ - __INIT_RUN__; + OVL1ADDR: file = "%O.1", start = __HIMEM2__ - __OVERLAYSIZE__, size = $0002; + OVL1: file = "%O.1", start = __HIMEM__ - __OVERLAYSIZE__, size = __OVERLAYSIZE__; + OVL2ADDR: file = "%O.2", start = __HIMEM2__ - __OVERLAYSIZE__, size = $0002; + OVL2: file = "%O.2", start = __HIMEM__ - __OVERLAYSIZE__, size = __OVERLAYSIZE__; + OVL3ADDR: file = "%O.3", start = __HIMEM2__ - __OVERLAYSIZE__, size = $0002; + OVL3: file = "%O.3", start = __HIMEM__ - __OVERLAYSIZE__, size = __OVERLAYSIZE__; + OVL4ADDR: file = "%O.4", start = __HIMEM2__ - __OVERLAYSIZE__, size = $0002; + OVL4: file = "%O.4", start = __HIMEM__ - __OVERLAYSIZE__, size = __OVERLAYSIZE__; + OVL5ADDR: file = "%O.5", start = __HIMEM2__ - __OVERLAYSIZE__, size = $0002; + OVL5: file = "%O.5", start = __HIMEM__ - __OVERLAYSIZE__, size = __OVERLAYSIZE__; + OVL6ADDR: file = "%O.6", start = __HIMEM2__ - __OVERLAYSIZE__, size = $0002; + OVL6: file = "%O.6", start = __HIMEM__ - __OVERLAYSIZE__, size = __OVERLAYSIZE__; + OVL7ADDR: file = "%O.7", start = __HIMEM2__ - __OVERLAYSIZE__, size = $0002; + OVL7: file = "%O.7", start = __HIMEM__ - __OVERLAYSIZE__, size = __OVERLAYSIZE__; + OVL8ADDR: file = "%O.8", start = __HIMEM2__ - __OVERLAYSIZE__, size = $0002; + OVL8: file = "%O.8", start = __HIMEM__ - __OVERLAYSIZE__, size = __OVERLAYSIZE__; + OVL9ADDR: file = "%O.9", start = __HIMEM2__ - __OVERLAYSIZE__, size = $0002; + OVL9: file = "%O.9", start = __HIMEM__ - __OVERLAYSIZE__, 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, optional = 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..861e19faf 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, 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, diff --git a/libsrc/c64/crt0.s b/libsrc/c64/crt0.s index 24fe4376b..5a69f1584 100644 --- a/libsrc/c64/crt0.s +++ b/libsrc/c64/crt0.s @@ -3,13 +3,13 @@ ; .export _exit + .exportzp init_load_, init_run_ .export __STARTUP__ : absolute = 1 ; Mark as startup + .import initlib, donelib - .import zerobss - .import callmain + .import move_init, zerobss, callmain .import RESTOR, BSOUT, CLRCH - .import __RAM_START__, __RAM_SIZE__ ; Linker generated - .import __STACKSIZE__ ; Linker generated + .import __HIMEM__ ; from configure file .importzp ST .include "zeropage.inc" @@ -19,17 +19,16 @@ ; ------------------------------------------------------------------------ ; Startup code -.segment "STARTUP" +; Two zero-page pointers are needed before any zero-page stuff is saved. +; Choose locations that are not used by anything. -Start: +init_load_ := FREKZP +init_run_ := FREKZP+2 -; Save the zero-page locations that we need. - ldx #zpspace-1 -L1: lda sp,x - sta zpsave,x - dex - bpl L1 +.segment "STARTUP" + +Start: ; Switch to the second charset. @@ -39,35 +38,30 @@ 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 often can let us rerun the program without reloading it. -; Call the module constructors. + ldx moveinit + 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 move_init + dec moveinit ; set to false + +; Save space by putting the rest of the start-up code in the INIT segment, +; which can be re-used by the heap. - jsr callmain +L0: jsr initstart ; Back from main() [this is also the exit() entry]. Run the module destructors. @@ -98,14 +92,51 @@ L2: lda zpsave,x rts + ; ------------------------------------------------------------------------ -; Data -.segment "ZPSAVE" +.segment "INIT" -zpsave: .res zpspace +initstart: + +; Save the zero-page locations that we need. -.bss + ldx #zpspace-1 +L1: lda sp,x + sta zpsave,x + dex + bpl L1 + +; Clear the BSS data. + + jsr zerobss + +; Set up the stack. + + lda #<__HIMEM__ + ldx #>__HIMEM__ + 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 -spsave: .res 1 mmusave:.res 1 +spsave: .res 1 +moveinit: + .byte 1 + +.segment "ZPSAVE" + +zpsave: .res zpspace diff --git a/libsrc/common/moveinit.s b/libsrc/common/moveinit.s new file mode 100644 index 000000000..e9cd5fb64 --- /dev/null +++ b/libsrc/common/moveinit.s @@ -0,0 +1,54 @@ +; +; 2015-10-04, Greg King +; + + .export move_init + + .import __INIT_LOAD__, __INIT_RUN__, __INIT_SIZE__ ; Linker-generated + .importzp init_load_, init_run_ + + .macpack cpu + .macpack generic + + +; 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. + +move_init: + lda #<__INIT_LOAD__ + ldx #>__INIT_LOAD__ + >__INIT_SIZE__ + sta init_load_ + stx init_load_+1 + lda #<__INIT_RUN__ + ldx #>__INIT_RUN__ + >__INIT_SIZE__ + sta init_run_ + stx init_run_+1 + +; First, move the last, partial page. +; Then, move all of the full pages. + + ldx #>__INIT_SIZE__ + 1 ; number of pages, including partial + ldy #<__INIT_SIZE__ ; size of partial page +.if .cpu & CPU_ISET_65SC02 + bra L3 +.else + jmp L3 +.endif + +L1: dec init_load_+1 + dec init_run_+1 + +L2: dey + lda (init_load_),y + sta (init_run_),y + tya +L3: bnz L2 ; page not finished + + dex + bnz L1 ; move next page + rts -- 2.39.5