Mercurial > hg > index.cgi
changeset 24:9586c547fcfa
Initialize the memory bookkeeping stuff at startup
| author | William Astle <lost@l-w.ca> |
|---|---|
| date | Thu, 10 Nov 2022 21:29:47 -0700 |
| parents | 4b4806a32701 |
| children | 9593401d23cf |
| files | src/lwbasic.s |
| diffstat | 1 files changed, 22 insertions(+), 0 deletions(-) [+] |
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--- a/src/lwbasic.s Wed Nov 09 23:07:33 2022 -0700 +++ b/src/lwbasic.s Thu Nov 10 21:29:47 2022 -0700 @@ -195,6 +195,15 @@ org 0 dpstart equ * ; start of direct page memtop rmb 2 ; absolute top of memory in 64K memory map +memsize rmb 2 ; top of memory not reserved +freetop rmb 2 ; top of free memory (bottom of string space) +stringtab rmb 2 ; bottom of used string space +progtext rmb 2 ; pointer to start of program text +vartabint rmb 2 ; pointer to start of integer scalars +vartabfloat rmb 2 ; pointer to start of floating point scalars +vartabstring rmb 2 ; pointer to start of string scalars +objecttab rmb 2 ; pointer to start of arrays and other variable sized objects +freestart rmb 2 ; pointer to start of unallocated memory readlinenoecho rmb 1 ; if nonzero, the readline routine won't echo its input rmb 0x71-* ; align RSTFLG/RSTVEC for stock ROM compatibility RSTFLG rmb 1 ; 0x55 if RSTVEC is valid @@ -436,7 +445,20 @@ ldx #ROMSTART-1 ; point to top of memory endc coldstart2 stx memtop ; save absolute top of memory + stx memsize ; save top of unreserved memory + stx stringtab ; mark string space as empty + leax -200,x ; allocate 200 bytes of string space + stx freetop ; save top of free memory leas ,x ; put the stack there + ldx #heapstart ; point to start of free memory + stx progtext ; put the start of the program there + clr ,x+ ; put a NULL pointer to mark end of program + clr ,x+ + stx vartabint ; put start of integer variables at end of program + stx vartabfloat ; put start of floating point variables after that + stx vartabstring ; put start of string variables after that + stx objecttab ; also put the start of large objects there + stx freestart ; mark the start of free memory ldx #warmstart ; set up warm start handler stx RSTVEC lda #0x55 ; activate warm start handler