Mercurial > hg > index.cgi
comparison src/memory.s @ 136:e49bd0493baf
Checkpoint updates to immediate mode program editing and some memory handling
| author | William Astle <lost@l-w.ca> |
|---|---|
| date | Fri, 12 Jul 2024 23:29:45 -0600 |
| parents | 3a4cb89a419c |
| children |
comparison
equal
deleted
inserted
replaced
| 135:3a4cb89a419c | 136:e49bd0493baf |
|---|---|
| 50 sta ,x+ ; save new byte in insert location | 50 sta ,x+ ; save new byte in insert location |
| 51 leau 1,u ; move to next source byte | 51 leau 1,u ; move to next source byte |
| 52 leay -1,y ; done all source bytes? | 52 leay -1,y ; done all source bytes? |
| 53 bne mem_insert3 ; brif not | 53 bne mem_insert3 ; brif not |
| 54 puls d,x,pc ; clean up stack and return | 54 puls d,x,pc ; clean up stack and return |
| 55 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
| 56 ; Block copy routines. There are two routines here. One for moving a block upward in memory and one for moving the block | |
| 57 ; downward in memory. Which one is used doesn't matter if the source and destination do not overlap. However, if the | |
| 58 ; source and destination do overlap, the direction that needs to be used depends on whether the source is after or | |
| 59 ; before the destination. There are three entry points below. One is a general block copy, one is for moving upward | |
| 60 ; and one is for moving downward. All entry points have the same input conditions. | |
| 61 ; | |
| 62 ; Entry: | |
| 63 ; X: Destination pointer | |
| 64 ; U: Source pointer | |
| 65 ; Y: Length of the block to copy | |
| 66 ; | |
| 67 ; General copy. This just dispatches either mem_copyup or mem_copydn based on whether the source is before or after | |
| 68 ; the destination. | |
| 69 mem_copy pshs u ; save source address for compare | |
| 70 cmpx ,s++ ; is the destination below or above? | |
| 71 blo mem_copydn ; brif destination is below the source - we're copying downward | |
| 72 ; fall through ; we're copying upward here | |
| 73 ; Copy Y bytes from (U) to (X), working from the top down | |
| 74 mem_copyup tfr y,d ; need to move pointers to the end of the block | |
| 75 leax d,x | |
| 76 leau d,u | |
| 77 mem_copyup0 lda ,-u ; copy a byte upward | |
| 78 sta ,-x | |
| 79 leay -1,y ; done yet? | |
| 80 bne mem_copyup0 | |
| 81 rts | |
| 82 ; Copy Y bytes from (U) to (X), working from bottom up | |
| 83 mem_copydn lda ,u+ ; copy a byte downward | |
| 84 sta ,x+ | |
| 85 leay -1,y ; done yet? | |
| 86 bne mem_copydn ; brif not | |
| 87 mem_checkptr0 rts | |
| 88 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
| 89 ; Check for D bytes of free memory | |
| 90 mem_checkd addd freestart ; add to current start of free memory | |
| 91 ; fall through to test the resulting pointer | |
| 92 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
| 93 ; Check if the address in D is within the free memory area allowing for a buffer for the system stack. | |
| 94 mem_checkptr addd #stackheadroom ; add in the stack buffer space to the pointer | |
| 95 sts ,--s ; get the current stack pointer somewhere | |
| 96 cmpd ,s++ ; did the pointer run into the stack pointer? | |
| 97 blo mem_checkptr0 ; brif not - no error | |
| 98 OMERROR ldb #err_om ; raise an OM error | |
| 99 jmp ERROR | |
| 55 *pragmapop list | 100 *pragmapop list |