.PROC Allocate,4
FindSeg .EQU 41
SegBase .EQU Temp1
Bank .EQU Temp2
SegNum .EQU Temp3
NumPages .EQU Temp4
EnterProc RetAddr
PULL SegBase
PULL Bank
PULL SegNum
PULL NumPages
P_A_Word NumPages,Pages
SOSCall Find_Seg,Param
BEQ $1 ; If it worked,great
SOSCall Find_Seg,Param ; Else try again!
$1 BEQ $2
LDA #0 ; 2 failures ==> return 0 pages
STA Pages
STA Pages+1
$2 LDA SPage ; Send back starting address
LDY #1 ; in high byte!!
STA (SegBase),Y
DEY
TYA
STA (SegBase),Y
A_P_Word Pages,NumPages
A_P_Byte SBank,Bank
A_P_Byte Seg, SegNum
Return RetAddr
Param .BYTE 06
SrchMde .BYTE 02 ; Can cross more than one boundary
SegId .BYTE 30 ; First user segment?
Pages .WORD
SBank .BYTE
SPage .BYTE
.WORD
Seg .BYTE
RetAddr .WORD
.PROC DeAllocate,1
; PROCEDURE DeAllocate(SegNum:INTEGER); EXTERNAL;
Release_Seg .EQU 45
EnterProc RetAddr
PULL SegNum
LDA SegNum
BEQ Ret ; Don't release all segs!
SOSCALL Release_Seg,Param
Ret Return RetAddr
Param .BYTE 1
SegNum .WORD ; Only first byte used by SOS, but PULL
; needs 2
RetAddr .WORD
.END
================================================================
; This file contains an assembly language procedure which moves
; bytes from one bank to another. Use this from Pascal to get
; access to the rest of the bank space in larger machines.
; This can allow you to do SOS Request-Seg calls and use
; that area for data storage for later use or to pass to an
; assembly procedure. This procedure does two slightly difficult
; things :
;
; 1. it avoids holes in bank memory map, and
; 2. it switches banks on both source and destination at the
; right times.
;
; Pascal declaration is:
; PROCEDURE FetchBytes(SrcBank:INTEGER; Source:INTEGER;
; DstBank:INTEGER; Dest:INTEGER;
; PageCount:INTEGER; Count:INTEGER
; ); EXTERNAL;
;
; The procedure will copy 256*PageCount+Count bytes from
; Source (a bank pointer to bank pair starting with SrcBank) to
; Dest (a bank pointer to bank pair starting with DstBank);
; A SrcBank or DstBank of -1 means "in Pascal's bank pair"
; Thus FetchBytes(-1,Atsign(S),-1,Atsign(D),0,C) ==
; MoveLeft(S,D,C)
;
; RESTRICTIONS:
; 1. Equivalent to a moveleft (ascending transfer)
; 2. Cannot reach top and bottom (system) banks,
; and "real" addresses must be offset
; by $2000 to render bank addresses
;
; ALGORITHM:
; 1. If we're moving X*65535 +Y*256 + Z bytes, then
; 2. First move Y pages to clear middle byte of Count
; 3. Then use middle byte to move X*256 pages,
; 4. Finally, move Z bytes in last page.
; ==============================================================
; MACRO Defs
.MACRO PULL
PLA
STA %1
PLA
STA %1+1
.ENDM
.MACRO PUSH
LDA %1+1
PHA
LDA %1
PHA
.ENDM