Mercurial > hg > Members > kono > nitros9-code
annotate level2/modules/kernel/fmem.asm @ 3195:6eb2edad80d8
L2: Introduce symbol KrnBlk to define kernel block number
This is the block number that the kernel is loaded into. This is
platform-specific, a function of the behaviour of the platform MMU/DAT.
CRCs are unaffected by this change.
| author | Neal Crook <foofoobedoo@gmail.com> |
|---|---|
| date | Thu, 01 Jun 2017 22:13:49 +0100 |
| parents | 039ddb7c8ad7 |
| children |
| rev | line source |
|---|---|
| 1145 | 1 ************************************************** |
| 2 * System Call: F$Mem | |
| 3 * | |
| 4 * Function: Resize data memory area | |
| 5 * | |
| 6 * Input: D = Desired memory area (in bytes) | |
| 7 * | |
| 8 * Output: Y = Address of new memory area upper bound | |
| 9 * D = New memory area size in bytes | |
| 10 * | |
| 11 * Error: CC = C bit set; B = error code | |
| 12 * | |
| 13 FMem ldx <D.Proc get current process pointer | |
| 14 ldd R$D,u get requested memory size | |
| 15 beq L0638 he wants current size, return it | |
| 16 addd #$00FF round up to nearest page | |
| 17 bcc L05EE no overflow, skip ahead | |
| 18 ldb #E$MemFul get mem full error | |
| 19 rts return | |
| 20 | |
| 21 L05EE cmpa P$PagCnt,x match current page count? | |
| 22 beq L0638 yes, return it | |
| 23 pshs a save page count | |
| 24 bhs L0602 he's requesting more, skip ahead | |
| 25 deca subtract a page | |
| 26 ldb #($100-R$Size) get size of default stack - R$Size | |
| 27 cmpd P$SP,x shrinking it into stack? | |
| 28 bhs L0602 no, skip ahead | |
| 29 ldb #E$DelSP get error code (223) | |
| 30 bra L0627 return error | |
| 31 L0602 lda P$PagCnt,x get page count | |
| 32 adda #$1F round it up | |
| 33 lsra divide by 32 to get block count | |
| 34 lsra | |
| 35 lsra | |
| 36 lsra | |
| 37 lsra | |
| 38 ldb ,s | |
| 39 addb #$1F | |
| 40 bcc L0615 still have room, skip ahead | |
| 41 ldb #E$MemFul | |
| 42 bra L0627 | |
| 43 L0615 lsrb divide by 32 to get block count | |
| 44 lsrb | |
| 45 lsrb | |
| 46 lsrb | |
| 47 lsrb | |
| 48 IFNE H6309 | |
| 49 subr a,b same count? | |
| 50 ELSE | |
| 1239 | 51 pshs a |
| 52 subb ,s+ | |
| 1145 | 53 ENDC |
| 54 beq L0634 yes, save it | |
| 55 bcs L062C overflow, delete the ram we just got | |
| 56 os9 F$AllImg allocate the image in DAT | |
| 57 bcc L0634 no error, skip ahead | |
| 58 L0627 leas 1,s purge stack | |
| 59 L0629 orcc #Carry set carry for error | |
| 60 rts return | |
| 61 | |
| 62 L062C equ * | |
| 63 IFNE H6309 | |
| 64 addr b,a | |
| 65 ELSE | |
| 1239 | 66 pshs b |
| 67 adda ,s+ | |
| 1145 | 68 ENDC |
|
3123
039ddb7c8ad7
l2 kernel: Remove tabs and trailing whitespace, align comments
Neal Crook <foofoobedoo@gmail.com>
parents:
1239
diff
changeset
|
69 negb |
|
039ddb7c8ad7
l2 kernel: Remove tabs and trailing whitespace, align comments
Neal Crook <foofoobedoo@gmail.com>
parents:
1239
diff
changeset
|
70 os9 F$DelImg |
| 1145 | 71 L0634 puls a restore requested page count |
| 72 sta P$PagCnt,x save it into process descriptor | |
| 73 L0638 lda P$PagCnt,x get page count | |
| 74 clrb clear LSB | |
| 75 std R$D,u save mem byte count to caller | |
| 76 std R$Y,u save memory upper limit to caller | |
| 77 rts return |