**************************************** * Basic Error Macro * **************************************** _Err mac bcc NoErr do ]0 ; (DO if true) jsr PgmDeath ; this is conditionally compiled if str ]1 ; we pass in an error statement else ; (ELSE) jmp PgmDeath0 ; we just call the simpler error handler fin ; (FIN) NoErr eom ; ; Dereference a handle that is on the top of the stack ; _Deref MAC phb ; save caller's data bank register pha ; push high word of handle on stack plb ; sets B to the bank byte of the pointer lda |$0002,x ; load the high word of the master pointer pha ; and save it on the stack lda |$0000,x ; load the low word of the master pointer tax ; and return it in X pla ; restore the high word in A plb ; pull the handle's high word high byte off the ; stack plb ; restore the caller's data bank register <<< _Mul128 mac asl asl asl asl asl asl asl <<< ; Possible optimization (assumes accumulator is <512). 8 cycles/5 bytes vs 14 cycles/7 bytes ; cmp #$0100 ; xba ; ror _Div16 mac lsr lsr lsr lsr <<< _R0W0 mac ; Read Bank 0 / Write Bank 0 ldal STATE_REG and #$FFCF stal STATE_REG <<< _R0W1 mac ; Read Bank 0 / Write Bank 1 ldal STATE_REG ora #$0010 stal STATE_REG <<< _R1W1 mac ; Read Bank 0 / Write Bank 1 ldal STATE_REG ora #$0030 stal STATE_REG <<< _PushReg mac ; Used to save/restore registers when calling subroutines. pha phx phy <<< _PullReg mac ply plx pla <<< _PushReg2 mac ; Variation to also save the P-register to preserve m/x pha phx phy php <<< _PullReg2 mac plp ply plx pla <<< jne mac beq *+5 jmp ]1 <<< jeq mac bne *+5 jmp ]1 <<< jcc mac bcs *+5 jmp ]1 <<< jcs mac bcc *+5 jmp ]1 <<< min mac cmp ]1 bcc mout lda ]1 mout <<< ; Increment a value mod some number. incmod mac inc cmp ]1 bcc out lda #0 out <<< decmod mac dec bpl out lda ]1 dec out <<< adcmod mac adc ]1 cmp ]2 bcc out sbc ]2 out <<< sbcmod mac sbc ]1 bpl out clc adc ]2 out <<< asr16 mac cmp #$8000 ror <<< asr8 mac cmp #$80 ror <<< ; Inline macros for fast calculation of some internal values _TileStoreOffset mac lda ]2 asl tay lda ]1 asl ; Assume in range, so asl puts a 0 bit into the carry adc TileStoreYTable,y <<< _TileStoreOffsetX mac lda ]2 asl tax lda ]1 asl ; Assume in range, so asl puts a 0 bit into the carry adc TileStoreYTable,x <<< _; Macro variant to calculate inline from any source _SpriteVBuffAddr mac lda ]2 clc adc #NUM_BUFF_LINES xba adc ]1 <<< ; Macro to define script steps ScriptStep MAC IF #=]5 dw {]1+{{]5&#$000F}<<8}},]2,]3,]4 ELSE dw ]1,]2,]3,]4 FIN <<< ; A specialized CopyMaskedWord macro that draws a tile from a direct page workspace. Used ; to render fringe tiles and sprite tiles when BG1 is active. If there is no second background, ; then one should use the optimized functions which assumes a PEA opcode and only ; needs to copy data words ; ; ]1 : tiledata direct page address , the tilemask direct page address is tiledata + 32 ; ]2 : code field offset CopyMaskedWordD MAC lda ]1+32 ; load the mask value bne mixed ; a non-zero value may be mixed ; This is a solid word lda #$00F4 ; PEA instruction sta: ]2,y lda ]1 ; load the tile data sta: ]2+1,y ; PEA operand bra next mixed cmp #$FFFF ; All 1's in the mask is fully transparent beq transparent ; This is the slowest path because there is a *lot* of work to do. So much that it's ; worth it to change up the environment to optimize things a bit more. ; ; Need to fill in the first 10 bytes of the JMP handler with the following code sequence ; ; lda (00),y ; and #MASK ; ora #DATA lda #$004C ; JMP instruction sta: ]2,y ldx _X_REG ; Get the addressing offset ldal JTableOffset,x ; Get the address offset and add to the base address adc _BASE_ADDR ; of the current code field line adc #{]2&$F000} ; adjust for the current row offset sta: ]2+1,y tay ; This becomes the new address that we use to patch in txa ; Get the offset and render a LDA (dp),y instruction sep #$20 sta: $0001,y ; LDA (00),y operand lda #$B1 sta: $0000,y ; LDA (00),y opcode lda #$29 sta: $0002,y ; AND #$0000 opcode lda #$09 sta: $0005,y ; ORA #$0000 opcode rep #$20 lda ]1+32 ; insert the tile mask and data into the exception sta: $0003,y ; handler. lda ]1 sta: $0006,y lda #$0D80 ; branch to the prologue (BRA *+15) sta: $0008,y ldy _Y_REG ; restore original y-register value and move on bra next ; This is a transparent word, so just show the second background layer transparent lda #$00B1 ; LDA (dp),y instruction sta: ]2,y lda _X_REG ; X is the logical tile offset (0, 2, 4, ... 82) left-to-right ora #$4800 ; put a PHA after the offset sta: ]2+1,y next eom ; Macros to use in the Masked Tile renderer ; ; ]1 : tiledata offset ; ]2 : tilemask offset ; ]3 : code field offset CopyMaskedWord MAC ldal ]2,x ; load the mask value bne mixed ; a non-zero value may be mixed ; This is a solid word lda #$00F4 ; PEA instruction sta: ]3,y ldal ]1,x ; load the tile data sta: ]3+1,y ; PEA operand bra next mixed cmp #$FFFF ; All 1's in the mask is fully transparent beq transparent ; This is the slowest path because there is a *lot* of work to do. So much that it's ; worth it to change up the environment to optimize things a bit more. ; ; Need to fill in the first 8 bytes of the JMP handler with the following code sequence ; ; lda (00),y ; and #MASK ; ora #DATA lda #$004C ; JMP instruction sta: ]3,y ldx _X_REG ; Get the addressing offset ldal JTableOffset,x ; Get the address offset and add to the base address ora _BASE_ADDR ; of the current code field row (2 rows per bank) $0000 or $8000 ora #{]3&$7000} ; adjust for the current line offset within the row sta: ]3+1,y tay ; This becomes the new address that we use to patch in txa ; Get the offset and render a LDA (dp),y instruction sep #$20 sta: $0001,y ; LDA (00),y operand lda #$B1 sta: $0000,y ; LDA (00),y opcode lda #$29 sta: $0002,y ; AND #$0000 opcode lda #$09 sta: $0005,y ; ORA #$0000 opcode rep #$20 ldx _T_PTR ; restore the original x-register value ldal ]2,x ; insert the tile mask and data into the exception sta: $0003,y ; handler. ldal ]1,x sta: $0006,y ; Copy the top 9 bytes down. We have 23 bytes of space and are only using 8. Since 9 + 8 = 17 < 23, we ; can save 3 cycles per word by eliminating the BRA instruction ; lda #$0D80 ; branch to the prologue (BRA *+15) ; sta: $0008,y lda: $0017,y sta: $0008,y lda: $0019,y sta: $000A,y lda: $001B,y sta: $000C,y lda: $001D,y sta: $000E,y lda: $001E,y sta: $000F,y ldy _Y_REG ; restore original y-register value and move on bra next ; This is a transparent word, so just show the second background layer transparent lda #$00B1 ; LDA (dp),y instruction sta: ]3,y lda _X_REG ; X is the logical tile offset (0, 2, 4, ... 82) left-to-right ora #$4800 ; put a PHA after the offset sta: ]3+1,y next eom