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Digital-Research-Source-Code/MPM OPERATING SYSTEMS/MPM-86/MPM-86 2.0 SOURCES/02/ML.MEM
Sepp J Morris 31738079c4 Upload
Digital Research
2020-11-06 18:50:37 +01:00

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;*****************************************************
;*
;* Memory List Functions
;*
;*****************************************************
;=============
mlalloc_entry: ; Alloc from Mem List
;=============
; Create a MAU from a Memory List. Memory List is a
; linked list of MDs in memory order (low first). It
; is assumed that units in the Memory List are paragraphs
; input: DX = address of MPB in u_wrkseg
; BX = ML root in SYSDAT
; output: BX = address of MAU
; = 0 if error
; CX = Error Code
mov si,dx
sub ax,ax ! mov cx,ax ! mov dx,0ffffh
; AX = MD w/best score
; DX = best score
; CX = # partitions used
; SI -> MPB in u_wrkseg
push ax ! push cx
mla_nmd:cmp m_link[bx],0 ! je mla_found
push bx ! push dx ! push si
call mla_value
pop si ! pop dx ! pop bx
cmp cx,dx ! jae mla_next
mov dx,cx ! pop cx ! mov cx,ax
pop ax ! mov ax,bx
push ax ! push cx
cmp dx,0 ! je mla_found
mla_next: mov bx,m_link[bx]
jmps mla_nmd
mla_found:
pop cx ! pop ax
cmp ax,0 ! je mla_err
mov bx,ax ! mov ax,cx
jmp mla_makemau
mla_err:sub bx,bx ! mov cx,e_no_memory
mla_out:ret
mla_value:
;---------
; input: BX = ML element Root
; SI = MPB in u_wrkseg
; output: CX = value (0=perfect,0ffffh=no fit)
; AX = # of elements
push es ! mov es,u_wrkseg
sub ax,ax ! mov dx,0
; AX = # of partitions
; DX = total length so far
mov di,m_link[bx]
cmp di,0 ! je mlav_err
; we have a list
cmp es:mpb_start[si],0 ! je mlav_next
;an absolute request
mov cx,m_start[di] ! add cx,(2*satlen)
cmp es:mpb_start[si],cx ! jb mlav_err
;it starts after our start
add cx,m_length[di] ! sub cx,(2*satlen)
cmp es:mpb_start[si],cx ! jae mlav_err
;this list satisfies ABS requirement
mlav_next: mov cx,es:mpb_max[si]
cmp cx,dx ! jb mlav_chk
mlav_add: cmp ax,0 ! je mlav_ad1
push ax
mov ax,m_start[bx]
add ax,m_length[bx]
cmp ax,m_start[di] ! pop ax ! je mlav_ad1
jmps mlav_chkmin
mlav_ad1: inc ax ! add dx,m_length[di]
mov bx,di ! mov di,m_link[bx]
cmp di,0 ! jne mlav_next
mlav_chkmin: mov cx,es:mpb_min[si]
add cx,(2*satlen)
cmp cx,dx ! jbe mlav_calc
jmps mlav_err
mlav_chk: add cx,(2*satlen)
cmp cx,dx ! ja mlav_add
mlav_calc: ; HERE IS WHERE WE GIVE THIS SET A VALUE.
; IT CAN SATIFY THE REQUEST.
; ALGORITHM: (for now)
; #partitions = #partitions + 1 if next
; to contiquous memory
; value = (abs(max-length) SHR 4) +
; ((#partitions-1) SHL 5)
; idea is that 8K = 1 partition to avoid
; gobbling all of our small partitions.
; we deal with 256 byte memory units so we
; won't overflow a word.
; AX = # partitions
; DX = memory size
push ax ! dec ax ! mov cl,5 ! shl ax,cl
mov cx,es:mpb_max[si]
add cx,(2*satlen)
cmp cx,dx ! jbe mlav_ab
xchg dx,cx
mlav_ab: sub dx,cx ! mov cl,4 ! shr dx,cl
add dx,ax ! mov cx,dx
pop ax ! pop es ! ret
mlav_err:
mov cx,0ffffh ! sub ax,ax
pop es ! ret
mla_makemau:
;-----------
; input: BX = address of ML element Root
; AX = number of elements
; output: BX = MAU address
cmp ax,1 ! jg mlam_getmd
mov si,m_link[bx] ! mov cx,m_link[si]
mov m_link[bx],cx ! mov bx,si
sub cx,cx ! mov m_plist[bx],cx
mov m_link[bx],cx
jmp mla_initmau
mlam_getmd:
push ax ! push bx
call getmd
mov di,bx ! pop bx ! pop ax
jcxz mlam_gotmd
sub bx,bx ! ret
mlam_gotmd:
mov m_link[di],0 ! mov m_length[di],0
mov si,m_link[bx] ! mov m_plist[di],si
mov cx,m_start[si] ! mov m_start[di],cx
mlam_next:
mov cx,m_length[si] ! add m_length[di],cx
dec ax ! cmp ax,0 ! je mlam_nomore
mov si,m_link[si] ! jmps mlam_next
mlam_nomore:
push bx
mov bx,m_link[si]
mov m_link[si],0
pop si ! mov m_link[si],bx
mov bx,di ! sub cx,cx ! ;jmp mla_initmau
mla_initmau:
;----------
; input: BX = address of MAU
; output: BX = address of MAU
; CX = 0
mov dx,m_start[bx] ! mov cx,m_length[bx]
push cx ! push es ! mov es,dx ! sub ax,ax
mov di,ax ! mov cx,((32*satlen)/2)
rep stos ax ! pop es
pop cx ! mov ds,dx
mov byte ptr .0,31
sub cx,(2*satlen) ! add dx,(2*satlen)
mov si,satlen ! mov sat_start[si],dx
mov sat_length[si],cx ! mov sat_nall[si],0
mov ds,sysdat
sub cx,cx ! ret
;============
mlfree_entry: ; Free from Mem List
;============
; input: DX = MAU address
; BX = ML Root
mov si,dx
cmp m_plist[si],0 ! je mlf_freeone
mov di,si
mov si,m_plist[si]
mlf_nmd: cmp si,0 ! je mlf_endfree
push m_link[si] ! push bx ! push di
call ml_insert
pop di ! pop bx ! pop si ! jmps mlf_nmd
mlf_endfree:
mov bx,di ! call freemd
jmps mlf_exit
mlf_freeone:
call ml_insert
mlf_exit:
sub bx,bx ! mov cx,bx ! ret
ml_insert:
;---------
; input: SI = address of MD to insert
; BX = ML Root
mov di,m_link[bx]
cmp di,0 ! je mli_ins
mov ax,m_start[di]
cmp ax,m_start[si] ! ja mli_ins
mov bx,di ! jmps ml_insert
mli_ins:mov ax,m_link[bx] ! mov m_link[bx],si
mov m_link[si],ax
ret