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view src/vars.s @ 73:2d52cd154ed1
Split some code into separate files for easier management
Because the source for lwbasic is so large, split it into several
different files to make it easier to navigate and modify. This is
part one of the split.
| author | William Astle <lost@l-w.ca> |
|---|---|
| date | Sun, 06 Aug 2023 00:12:29 -0600 |
| parents | |
| children | bb50ac9fdf37 |
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*pragmapush list *pragma list ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; Start of memory which has the direct page and other data. org 0 dpstart equ * ; start of direct page zero rmb 2 ; constant zero word used for faster zeroing of 16 bit registers binval rmb 2 ; arbitary binary value, usually a line number or integer 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 stackptr rmb 2 ; bottom of the "stack frame" stack (the actual stack is below here) progtext rmb 2 ; pointer to start of program text vartab rmb 2 ; pointer to start of integer 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 console_curptr rmb 2 ; current cursor pointer for console driver console_blnkdel rmb 1 ; cursor blink delay console_truelc rmb 1 ; set to nonzero if the console supports true lower case (gfx, etc.) filenum rmb 1 ; current input/output channel fileeof rmb 1 ; flag for whether last read detected EOF keyb_flags rmb 1 ; shift flags for the keyboard keyb_joystate rmb 1 ; joystick button state keyb_repdel rmb 1 ; repeat delay keyb_curscan rmb 1 ; current repeating scan code keyb_buffw rmb 2 ; keyboard ring buffer write pointer keyb_buffr rmb 2 ; keyboard ring buffer read pointer curline rmb 2 ; pointer to current line contline rmb 2 ; pointer to line for CONT contstmt rmb 2 ; interpretation pointer for CONT curstmt rmb 2 ; start of statement currently being interpreted endflag rmb 1 ; 00 = END, FF = STOP stringstackptr rmb 2 ; anonymous string descriptor stack pointer tok_skipkw rmb 1 ; flag for when skipping an unrecognized keyword tok_skipdt rmb 1 ; flag for when processing DATA tok_kwtype rmb 1 ; primary/secondary type flag for tokens tok_kwnum rmb 1 ; the actual token number tok_kwmatchl rmb 1 ; the length of the best match during lookup tok_kwmatch rmb 2 ; the current best matched token number val0 rmb val.size ; value accumulator 0 val1 rmb val.size ; value accumulator 1 rmb 0x71-* ; align RSTFLG/RSTVEC for stock ROM compatibility RSTFLG rmb 1 ; 0x55 if RSTVEC is valid RSTVEC rmb 2 ; points to warm start routine (must start with NOP) inputptr rmb 2 ; pointer to current program execution location rmb 0x100-* ; make sure the stuff that isn't direct page is outside of it SW3VEC rmb 3 ; SWI3 vector (for compatibility) SW2VEC rmb 3 ; SWI2 vector (for compatibility) SWIVEC rmb 3 ; SWI vector (for compatibility) NMIVEC rmb 3 ; NMI vector (for compatibility) IRQVEC rmb 3 ; IRQ vector (for compatibility) FRQVEC rmb 3 ; FIRQ vector (for compatibility) keyb_state rmb 8 ; rollover table state keyb_buff rmb keyb_bufflen ; the keyboard ring buffer linebuff rmb linebuffsize ; the line input buffer tokebuff rmb linebuffsize+50 ; make it as long as line buffer plus a margin stringstack rmb 5*stringstacknum ; reserve space for the anonymous string descriptor stack stringstackend equ * ; end of string stack buffer ifne *&0x1ff rmb 0x200-(*&0x1ff) endc textscreen rmb 0x200 ; the actual text screen (must be on 512 byte alignment) heapstart equ * ; start of dynamically allocated stuff ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; The heap has the following items in order: ; ; Program text: preceded by a NUL and pointed to by progtext ; Variable table: pointed to by vartab; contains records for all scalar and array variables ; Free space: unused memory between the object table and the stack; pointed to by freestart ; The stack: grows downward from the bottom of string space, pointed to by the stack pointer, obviously ; String space: garbage collected non-constant string data pointed to by freetop ; Reserved memory: immediately above string space; pointed to by memsize ; Actual top of RAM: top of reserved memory; pointed to by memtop ; ; The variable table consists of several symbol tables defined as follows: ; ; Pointer Size of entry Variable types ; vartabint 4 Integer scalars ; vartablong 6 Long integer scalars ; vartabfloat 7 Floating point scalars ; vartabstring 6 String scalars ; ; Each entry starts with 2 bytes for the variable name followed by the data payload. *pragmapop list