Mercurial > hg > Members > kono > nitros9-code
view level1/modules/kernel/fallbit.asm @ 2690:6e40b043d3e0 lwtools-port
Removed coco port, added coco1 and coco2 ports.
Cleaned term* descriptors to make unified between Level 1 and Level 2
| author | Boisy Pitre <boisy.pitre@nuance.com> |
|---|---|
| date | Thu, 19 Jul 2012 10:09:15 -0500 |
| parents | 505c8d261ef6 |
| children |
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************************************************** * System Call: F$AllBit * * Function: Sets bits in an allocation bitmap * * Input: X = Address of allocation bitmap * D = Number of first bit to set * Y = Bit count (number of bits to set) * * Output: None * * Error: CC = C bit set; B = error code * FAllBit ldd R$D,u get bit # to start with leau R$X,u get address of allocation bit map pulu y,x L065A pshs y,x,b,a bsr CalcBit calculate byte & position & get first bit mask tsta pshs a bmi L0671 lda ,x L0665 ora ,s leay -1,y beq L0689 lsr ,s bcc L0665 sta ,x+ L0671 tfr y,d sta ,s lda #$FF bra L067B L0679 sta ,x+ L067B subb #$08 bcc L0679 dec ,s bpl L0679 L0683 lsla incb bne L0683 ora ,x L0689 sta ,x clra leas 1,s puls pc,y,x,b,a * Calculate address of first byte we want, and which bit in that byte, from * a bit allocation map given the address of the map & the bit # we want to * point to * Entry: D=Bit # * X=Ptr to bit mask table * Exit: A=Mask to point to bit # within byte we are starting on * X=Ptr in allocation map to first byte we are starting on CalcBit pshs b IFNE H6309 lsrd divide bit # by 8 to calculate byte # to start lsrd allocating at lsrd addr d,x offset that far into the map ELSE lsra rorb lsra rorb lsra rorb leax d,x ENDC puls b lda #$80 andb #$07 round it down to nearest bit beq L06A6 L06A2 lsra decb bne L06A2 L06A6 rts ************************************************** * System Call: F$DelBit * * Function: Clears bits in an allocation bitmap * * Input: X = Address of allocation bitmap * D = Number of first bit to clear * Y = Bit count (number of bits to clear) * * Output: None * * Error: CC = C bit set; B = error code * FDelBit ldd R$D,u get bit # to start with leau R$X,u get addr. of bit allocation map pulu y,x L06AD pshs y,x,b,a bsr CalcBit coma pshs a bpl L06C4 lda ,x L06B8 anda ,s leay -1,y beq L06D8 asr ,s bcs L06B8 sta ,x+ L06C4 tfr y,d bra L06CA L06C8 clr ,x+ L06CA subd #$0008 bhi L06C8 beq L06D8 L06D1 lsla incb bne L06D1 coma anda ,x L06D8 sta ,x clr ,s+ puls pc,y,x,b,a ************************************************** * System Call: F$SchBit * * Function: Search bitmap for a free area * * Input: X = Address of allocation bitmap * D = Starting bit number * Y = Bit count (free bit block size) * U = Address of end of allocation bitmap * * Output: D = Beginning bit number * Y = Bit count * * Error: CC = C bit set; B = error code * FSchBit pshs u ldd R$D,u get start bit # ldx R$X,u get addr. of allocation bitmap ldy R$Y,u get bit count ldu R$U,u get address of end of allocation bitmap bsr L06F3 puls u std R$D,u sty R$Y,u rts L06F3 pshs u,y,x,b,a pshs y,b,a clr 8,s clr 9,s tfr d,y bsr CalcBit pshs a bra L0710 L0703 leay $01,y sty $05,s L0708 lsr ,s bcc L0714 ror ,s leax $01,x L0710 cmpx $0B,s bcc L0732 L0714 lda ,x anda ,s bne L0703 leay $01,y tfr y,d subd $05,s cmpd $03,s bcc L0739 cmpd $09,s bls L0708 std $09,s ldd $05,s std $01,s bra L0708 L0732 ldd $01,s std $05,s coma bra L073B L0739 std $09,s L073B leas $05,s puls pc,u,y,x,b,a