Mercurial > hg > Members > kono > nitros9-code
changeset 3193:489617e567c5
mfree.asm: Improve comment and remove trailing white-space
Infer functionality by code inspection and add comments accordingly.
Document bug that occurs when final block is free (does not occur on
coco but does occur on mc09).
| author | Neal Crook <foofoobedoo@gmail.com> |
|---|---|
| date | Tue, 30 May 2017 23:45:40 +0100 |
| parents | 5e48668f30b2 |
| children | 2ecebda8716b |
| files | level2/cmds/mfree.asm |
| diffstat | 1 files changed, 148 insertions(+), 106 deletions(-) [+] |
line wrap: on
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--- a/level2/cmds/mfree.asm Mon May 29 22:19:42 2017 +0100 +++ b/level2/cmds/mfree.asm Tue May 30 23:45:40 2017 +0100 @@ -18,28 +18,27 @@ use defsfile endc -tylg set Prgrm+Objct +tylg set Prgrm+Objct atrv set ReEnt+rev rev set $00 edition set 2 mod eom,name,tylg,atrv,start,size -u0000 rmb 1 -u0001 rmb 1 -u0002 rmb 2 -u0004 rmb 1 -u0005 rmb 1 +freeblks rmb 2 +mapsiz rmb 2 +* pages per block (ie, MS byte of block size) +ppblk rmb 1 +* 0: print number with leading spaces. 1: print number with leading 0. +leadzero rmb 1 +* u0006,7,8 store a 24-bit block begin/end address. u0006 rmb 1 u0007 rmb 1 u0008 rmb 1 -u0009 rmb 1 -u000A rmb 1 -u000B rmb 2 +bufstrt rmb 2 +bufcur rmb 2 linebuf rmb 80 -u005D rmb 7 -u0064 rmb 132 -u00E8 rmb 1135 +mapbuf rmb 1274 size equ . name fcs /Mfree/ @@ -50,148 +49,190 @@ Ftr fcs " ==== ======" fcs " Total: " -start leax linebuf,u get line buffer address - stx <u0009 - stx <u000B - lbsr L016E +start leax linebuf,u get line buffer address + stx <bufstrt and store it away + stx <bufcur current output position output buffer + + lbsr wrbuf print CR leay <Hdr,pcr - lbsr L0183 - lbsr L016E - lbsr L0183 - lbsr L016E - clr <u0000 - clr <u0001 - leax <u005D,u - os9 F$GBlkMp - sty <u0002 - sta <u0004 - ldy #$0000 -L00AA ldu #$0000 -L00AD tst ,x+ - beq L00BA - leay $01,y - cmpy <u0002 - bcs L00AD - bra L0109 + lbsr tobuf 1st line of header to output buffer + lbsr wrbuf ..print it + lbsr tobuf 2nd line of header to output buffer + lbsr wrbuf ..print it + + clr <freeblks total number of free blocks + clr <freeblks+1 + leax <mapbuf,u +* In: X = 1024-byte buffer +* Out: D = number of bytes per block +* Y = system memory block map size + os9 F$GBlkMp + sty <mapsiz save map size + sta <ppblk save MS byte of bytes per block + ldy #$0000 count of how many blocks we have inspected + +* Main loop +* look for a free block (an entry of 0 in the block map) +loop ldu #$0000 number of free blocks in this sequence +L00AD tst ,x+ is this block 0? + beq L00BA yes - found a free block + leay $01,y total number of blocks we have inspected + cmpy <mapsiz at the end of the map? + bcs L00AD no, so carry on looking + bra alldone yes, and the last block was not free, so we're done. + +* Block number in Y is the first free block of a sequence (tho maybe a sequence of 1) L00BA tfr y,d - bsr L0123 - lda <u0004 + bsr buf4hex append start block, in hex, to output buffer + lda <ppblk pshs y,a - clra - clrb -L00C4 addd $01,s - dec ,s + clra + clrb +L00C4 addd $01,s multiply start block by block size to get + dec ,s begin address bne L00C4 leas $03,s - std <u0006 - clr <u0008 - bsr L0133 -L00D2 leau u0001,u + std <u0006 2 MS bytes of block begin address + clr <u0008 1 LS byte of block begin address is 0 + bsr buf6hex append block begin address in hex, to output buffer + +* Look for the last free block in this sequence +L00D2 leau $01,u leay $01,y - cmpy <u0002 - beq L0109 + cmpy <mapsiz + beq alldone ??should never exit at this point, but +* on mc09 we do - terminate part-way through an entry. tst ,x+ - beq L00D2 - lda <u0004 + beq L00D2 haven't found it yet.. +last lda <ppblk pshs y,a - clra - clrb -L00E5 addd $01,s - dec ,s + clra + clrb +L00E5 addd $01,s multiply end block by block size to get + dec ,s end address bne L00E5 leas $03,s subd #$0001 - std <u0006 + std <u0006 2 MS bytes of block end address lda #$FF - sta <u0008 - bsr L0133 + sta <u0008 1 LS byte of block end address is $FF + bsr buf6hex append block end address in hex, to output buffer leax -$01,x tfr u,d - bsr L0123 - lbsr L0199 - addd <u0000 - std <u0000 - bsr L016E - bra L00AA -L0109 leay >Ftr,pcr - bsr L0183 - bsr L016E - bsr L0183 - tfr u,d - addd <u0000 - std <u0000 - bsr L0123 - bsr L0199 - bsr L016E - clrb - os9 F$Exit -L0123 pshs b,a - clr <u0005 + bsr buf4hex append number of blocks, in hex, to output buffer + lbsr L0199 append size, in decimal, to output buffer + + addd <freeblks + std <freeblks total number of blocks + bsr wrbuf print this entry + bra loop loop for next entry + +* All of the entries have been printed. Print the trailer and totals. +* Bug: if the last block is unused, it and any unused blocks before it will +* not get reported, *and* the formatting of the last entry will be messed up. +* That never happens on the Coco, because the last block is always used. +* It does happen on mc09 though. +alldone leay >Ftr,pcr + bsr tobuf 1st line of footer to output buffer + bsr wrbuf ..print it + bsr tobuf 2nd line of footer to output buffer + tfr u,d ..add total #blocks, total memory size + addd <freeblks + std <freeblks + bsr buf4hex append total number of blocks, in hex, to output buffer + bsr L0199 append total size, in decimal, to output buffer + bsr wrbuf ..print it +* Successful exit + clrb + os9 F$Exit + +* convert value in D to ASCII hex (4 chars). Append to output buffer, then append "SPACE" to output buffer +buf4hex pshs b,a + clr <leadzero bsr L0145 tfr b,a bsr L0145 - lda #$20 - bsr L0164 + lda #C$SPAC append a space + bsr bufchr puls pc,b,a -L0133 clr <u0005 + +* convert value in u0006,7,8 to ASCII hex (6 chars). Append to output buffer, then append "SPACE" to output buffer +buf6hex clr <leadzero lda <u0006 bsr L0145 lda <u0007 bsr L0145 lda <u0008 bsr L0145 - lda #$20 - bra L0164 + lda #C$SPAC append a space + bra bufchr + +* convert value in A to ASCII hex (2 chars). Append to output buffer. L0145 pshs a - lsra - lsra - lsra - lsra + lsra + lsra + lsra + lsra bsr L014F puls a L014F anda #$0F - tsta + tsta beq L0156 - sta <u0005 -L0156 tst <u0005 + sta <leadzero +L0156 tst <leadzero bne L015C lda #$F0 + +* FALL THROUGH +* Convert digit to ASCII with leading spaces, add to output buffer +* A is a 0-9 or A-F or $F0. +* Add $30 converts 0-9 to ASCII "0" - "9"), $F0 to ASCII "SPACE" +* leaves A-F >$3A so a further 7 is added so $3A->$41 etc. (ASCII "A" - "F") L015C adda #$30 cmpa #$3A - bcs L0164 + bcs bufchr adda #$07 -L0164 pshs x - ldx <u000B + +* FALL THROUGH +* Store A at next position in output buffer. +bufchr pshs x + ldx <bufcur sta ,x+ - stx <u000B + stx <bufcur puls pc,x -L016E pshs y,x,a +* Append CR to the output buffer then print the output buffer +wrbuf pshs y,x,a lda #C$CR - bsr L0164 - ldx <u0009 - stx <u000B - ldy #80 - lda #$01 - os9 I$WritLn + bsr bufchr + ldx <bufstrt address of data to write + stx <bufcur reset output buffer pointer, ready for next line. + ldy #80 maximum # of bytes - otherwise, stop at CR + lda #$01 to STDOUT + os9 I$WritLn puls pc,y,x,a -L0183 lda ,y + +* Append string at Y to output buffer. String is terminated by MSB=1 +tobuf lda ,y anda #$7F - bsr L0164 + bsr bufchr tst ,y+ - bpl L0183 - rts + bpl tobuf + rts DecTbl fdb 10000,1000,100,10,1 fcb $FF +* value in ?? is a number of blocks. Convert to bytes by multiplying by the page size. +* Convert to ASCII decimal, append to output buffer, append "k" to output buffer L0199 pshs y,x,b,a - lda <u0004 + lda <ppblk pshs a lda $01,s lsr ,s lsr ,s bra L01A9 + L01A7 lslb rola L01A9 lsr ,s @@ -212,12 +253,13 @@ bne L01D8 ldy #$2F20 lda #C$SPAC -L01D8 bsr L0164 +L01D8 bsr bufchr puls b,a bra L01B6 -L01DE bsr L0164 + +L01DE bsr bufchr lda #'k - bsr L0164 + bsr bufchr leas $02,s puls pc,y,x,b,a