mdw@git.distorted.org.uk Git - ssr/blob - StraySrc/Libraries/Sapphire/Modules/s/sprinkle

   1 ;
   2 ; sprinkle.s
   3 ;
   4 ; Handling of linked sprite areas (MDW)
   5 ;
   6 ; © 1995-1998 Straylight
   7 ;
   8
   9 ;----- Licensing note -------------------------------------------------------
  10 ;
  11 ; Sprinkle is free software; you can redistribute it and/or modify
  12 ; it under the terms of the GNU General Public License as published by
  13 ; the Free Software Foundation; either version 2, or (at your option)
  14 ; any later version.
  15 ;
  16 ; Sprinkle is distributed in the hope that it will be useful,
  17 ; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ; GNU General Public License for more details.
  20 ;
  21 ; You should have received a copy of the GNU General Public License
  22 ; along with Sprinkle.  If not, write to the Free Software Foundation,
  23 ; 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  24
  25 ;----- Standard header ------------------------------------------------------
  26
  27                 GET     libs:header
  28                 GET     libs:swis
  29
  30                 GET     libs:stream
  31
  32 ;----- External dependencies ------------------------------------------------
  33
  34                 IMPORT  version
  35
  36 ;----- Main code ------------------------------------------------------------
  37
  38                 AREA    |!!!Module$$Header|,CODE,READONLY
  39
  40                 DCD     0
  41                 DCD     sl__init
  42                 DCD     sl__final
  43                 DCD     0
  44                 DCD     sl__name
  45                 DCD     version
  46                 DCD     0
  47
  48 sl__name        DCB     "Sprinkle",0
  49
  50 ;----- Module header --------------------------------------------------------
  51
  52                 AREA    |Module$$Code|,CODE,READONLY
  53
  54 ; --- sl__init ---
  55 ;
  56 ; On entry:     --
  57 ;
  58 ; On exit:      R0-R6 corrupted
  59 ;
  60 ; Use:          Initialises our module.
  61
  62 sl__init        ROUT
  63
  64                 STMFD   R13!,{R14}              ;Save the link register
  65                 MOV     R0,#&1F                 ;SpriteV's vector number
  66                 ADR     R1,sl__spriteV          ;Point to my handler routine
  67                 MOV     R2,#0                   ;No workspace required
  68                 SWI     XOS_Claim               ;Try to claim the vector
  69                 LDMFD   R13!,{PC}               ;Return with that status
  70
  71                 LTORG
  72
  73 ; --- sl__final ---
  74 ;
  75 ; On entry:     --
  76 ;
  77 ; On exit:      R0-R6 corrupted
  78 ;
  79 ; Use:          Finalises our module when it's not needed any more.
  80
  81 sl__final       ROUT
  82
  83                 STMFD   R13!,{R14}              ;Save the link register
  84                 MOV     R0,#&1F                 ;SpriteV's vector number
  85                 ADR     R1,sl__spriteV          ;Point to the handler routine
  86                 MOV     R2,#0                   ;No workspace passed
  87                 SWI     XOS_Release             ;Release the vector
  88                 LDMFD   R13!,{PC}^              ;Return without hassle
  89
  90                 LTORG
  91
  92 ; --- sl__spriteV ---
  93 ;
  94 ; On entry:     R0 == reason code
  95 ;               R1 == pointer to sprite area, normally
  96 ;
  97 ; On exit:      As for OS_SpriteOp
  98 ;
  99 ; Use:          Catches calls to OS_SpriteOp, to allow linked sprite areas.
 100
 101 sl__spriteV     ROUT
 102
 103                 TST     R0,#&100                ;Is it named/user area?
 104                 MOVEQS  PC,R14                  ;No -- pass on the call then
 105
 106                 STMFD   R13!,{R10,R14}          ;Save some registers
 107
 108                 ; --- See if this call needs a sprite area in R1 ---
 109
 110                 AND     R14,R0,#&300            ;Get the magic extra bits
 111                 CMP     R14,#&100               ;Using a user area?
 112                 LDMNEFD R13!,{R10,PC}^          ;No -- then do nothing
 113
 114                 BIC     R14,R0,#&300            ;Clear the magic bits
 115                 CMP     R14,#8                  ;Does call need area in R1?
 116                 LDMCCFD R13!,{R10,PC}^          ;No -- do nothing then
 117
 118                 ; --- See if the sprite area is linked ---
 119
 120 10sl__spriteV   LDR     R14,[R1,#8]             ;Load offset to first sprite
 121                 CMP     R14,#24                 ;Enough space for link?
 122                 LDMCCFD R13!,{R10,PC}^          ;No -- do nothing then
 123
 124                 LDR     R10,[R1,#16]            ;Load first word of link
 125                 LDR     R14,sl__magic           ;Load the magic word
 126                 CMP     R10,R14                 ;Do these match?
 127                 LDMNEFD R13!,{R10,PC}^          ;No -- do nothing then
 128
 129                 ; --- Now worked it out then ---
 130
 131                 LDR     R10,[R1,#20]            ;Load the link pointer
 132                 CMP     R10,#0                  ;End of the list?
 133                 LDMEQFD R13!,{R10,PC}^          ;Yes -- do nothing then
 134
 135                 ; --- Now call OS_SpriteOp and post-process ---
 136
 137                 STMFD   R13!,{R0,R10}           ;Save reason code and link
 138                 MOV     R14,PC                  ;Get PC and flags in R14
 139                 ADD     R14,R14,#12             ;Point to postprocess code
 140                 STMFD   R13!,{R14}              ;Save those registers away
 141                 ADD     R14,R13,#12             ;Skip over stacked registers
 142                 LDMIA   R14,{R10,PC}^           ;And call OS_SpriteOp
 143
 144                 ; --- Returned from OS_SpriteOp ---
 145
 146                 LDMVSFD R13!,{R0,R1}            ;If failed, load link pointer
 147                 BVS     %10sl__spriteV          ;And loop backwards to next
 148                 ADD     R13,R13,#8              ;Point to old stack frame
 149                 LDMFD   R13!,{R10,R14,PC}^      ;And claim the call
 150
 151 sl__magic       DCB     "SPLK"
 152
 153                 LTORG
 154
 155 ;----- That's all, folks ----------------------------------------------------
 156
 157                 END