Mercurial > hg > Members > kono > nitros9-code
changeset 3088:fa4b4ae537c1
Add comments based on my learnings while debugging boot on multicomp09
| author | Neal Crook <foofoobedoo@gmail.com> |
|---|---|
| date | Tue, 13 Oct 2015 22:23:27 +0100 |
| parents | a938d0f26711 |
| children | 3244c2e1b6ed |
| files | level1/modules/kernel/krn.asm level1/modules/kernel/krnp2.asm |
| diffstat | 2 files changed, 42 insertions(+), 22 deletions(-) [+] |
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--- a/level1/modules/kernel/krn.asm Sat Oct 03 14:51:30 2015 -0500 +++ b/level1/modules/kernel/krn.asm Tue Oct 13 22:23:27 2015 +0100 @@ -260,24 +260,27 @@ GetMem equ * Initially I tried GetMem clra * that is redundant. See last line. RG L0158 ldx <D.FMBM - IFNE atari +* Free-memory bitmap. Bit7 of 0,x corresponds to page 0, bit6 to page 1 etc. +* Bit7 of 1,x corresponds to page 8, bit6 to page 9 etc, etc. + IFNE atari * In the Atari, memory $0000-$08FF is used by the system ldb #%11111111 - stb ,x mark $0000-$07FF as allocated - stb $1A,x mark $D000-$D7FF I/O area as allocated - ldb #%10000000 - stb 1,x mark $0800-$08FF as allocated - ELSE -* In the CoCo, memory $0000-$04FF is used by the system + stb ,x mark $0000-$07FF as allocated + stb $1A,x mark $D000-$D7FF I/O area as allocated + ldb #%10000000 + stb 1,x mark $0800-$08FF as allocated + ELSE +* For all (other) platforms, memory $0000-$04FF is used by the system ldb #%11111000 stb ,x - ENDC + ENDC +* For all platforms exclude high memory as defined (earlier) by D.MLIM clra ldb <D.MLIM negb tfr d,y negb - lbsr L065A + lbsr L065A in included fallbit.asm * jump into krnp2 here leax >P2Nam,pcr
--- a/level1/modules/kernel/krnp2.asm Sat Oct 03 14:51:30 2015 -0500 +++ b/level1/modules/kernel/krnp2.asm Tue Oct 13 22:23:27 2015 +0100 @@ -84,7 +84,7 @@ os9 F$SSvc ldx <D.PrcDBT os9 F$All64 - bcs L0081 + bcs fatalerr failed to allocate stx <D.PrcDBT sty <D.Proc tfr s,d @@ -94,31 +94,44 @@ lda #SysState sta P$State,y ldu <D.Init - bsr ChdDir - bcc L006A + +* ChdDir should identify system device, result in a call to IOCall which links and +* initialises IOMan then calls JmpBoot to load and validate the boot file + bsr ChdDir U = address of init module + bcc L006A success + +* Maybe we failed because we didn't have all the modules we needed? Load and +* validate the boot file and then try again. lbsr JmpBoot bsr ChdDir -L006A bsr OpenCons - bcc L0073 + +L006A bsr OpenCons U = address of init module, still + bcc L0073 success + +* Maybe we were able to get this far without needing anything from the boot file, but now +* we need it for the console device lbsr JmpBoot bsr OpenCons + +* Hmm. No check for success. Probably should "bcs fatalerr" here? + L0073 ldd InitStr,u leax d,u lda #$01 clrb ldy #$0000 os9 F$Chain -L0081 jmp [$FFFE] +fatalerr jmp [$FFFE] -* +* change directory * U = address of init module -ChdDir clrb +ChdDir clrb clear carry ldd <SysStr,u get system device - beq ChdDir10 branch if none - leax d,u - lda #READ.+EXEC. - os9 I$ChgDir else change directory to it -ChdDir10 rts + beq ChdDir10 branch if none - carry still clear + leax d,u address of the path list + lda #READ.+EXEC. access mode + os9 I$ChgDir change directory to it +ChdDir10 rts carry set -> error * open console device * U = address of init module @@ -715,8 +728,12 @@ os9 F$Link rts +* Attempt to load bootfile and validate the modules it contains * +* Entry: * U = address of init module +* Exit: +* CC Carry set on Error JmpBoot pshs u comb tst <D.Boot already booted?