ASM Optimized routines

[Xeda112358]

Oh, wow, awesome! I cannot believe I didn't see that, that is a source of some of my other optimisations from the original code o.O

[calc84maniac]

Here's a very optimized way to convert a 16-bit signed number into an 8-bit signed number in a with overflow handling (if hl<-128, a=-128; if hl>127, a=127). Two added bonus to being super small and super fast are that it destroys nothing and that you could easily modify it to make the input a 16-bit register other than hl.

Code: Select All | Copy To Clipboard

1 2 3 4 5 6 7 8 9 10 11 12 13

Signed16To8: ld a,l add a,a sbc a,a sub h ld a,l ret z ld a,h add a,a sbc a,a xor %01111111 ret

Implied challenge accepted!

Code: Select All | Copy To Clipboard

1 2 3 4 5 6 7 8 9 10 11

Signed16To8: ld a,l add a,a ld a,h adc a,l cp l ret z ld a,$7F ret p inc a ret

Edit: Whoops, misteak

Edit2: This routine is a failure, disregard its failtasticness

[Xeda112358]

I created this last night for my next project:

Code: Select All | Copy To Clipboard

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

PseudoRandWord: ;Outputs: ;     BC was the previous pseudorandom number ;     HL is the pseudorandom number ;f(n+1)=(241f(n)+257) mod 65536   ;65536 ;181 cycles, add 17 if called      ld hl,(randSeed)      ld c,l      ld b,h      add hl,hl      add hl,bc      add hl,hl      add hl,bc      add hl,hl      add hl,bc      add hl,hl      add hl,hl      add hl,hl      add hl,hl      add hl,bc      inc h      inc hl      ld (randSeed),hl      ret

There are a few other nice features, too. For example, every 16-bit value is hit if you run this 65536 times. Or, if you only read 1 byte (for example, H from the output), it will hit every 8-bit number once if you run this 256 times. Plus, it can be seeded, which has its own uses. This can be modified to be smaller, too, if you know what you are doing, but I just like the numbers 241 and 257. Anyways, it produces some nice results

P.S.-I used this in a routine called "ShuffleDeck" and it works very well.

[chickendude]

I don't understand the theory behind that algorithm, but you could save a couple clocks with SMC

And is ShuffleDeck a hint at what your next project might be?

[Xeda112358]

Yes, you can use SMC to save at least 6 cycles for RAM programs My next mini project is an app with some small games (including card games). I don't have my computer with me, but I will post a working sound routine next time I get a chance.

The way it works is that we are using mod 2¹⁶, so I selected two numbers relatively prime to 65536 (so any odd number, in this case). There are a few other conditions dealing with the Euler phi function, I believe, but I got lucky with the numbers I chose, so I didn't need to look it up. If you check, I chose prime numbers, specifically, because I figured those would give me the best shot.

If you choose the wrong values, you will get cycles of 2ⁿ. I am not sure how familiar you are with group theory, but essentially, you will be creating sub groups and the order (size) of a subgroup will always divide the order of the main group. So some values will make cycles of 32768, 16384, and other smaller powers of 2. (gah, there is so much cool theory behind this, but I don't have much time).


EDIT: ooh, here is a useful routine

Code: Select All | Copy To Clipboard

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

FindNumPages: ;Inputs: ;     The app base page is loaded in MemBank1 ;Outputs: ;     c flag set if the field was found ;     nc means the app header subfield was not found ;     A is the number of app pages ;     B is 0 ;     (HL) is the number of app pages      ld hl,4000h      ld bc,128      ld a,c      or a FNPLoop:      cpir      ret po      ret nz      inc a      cp (hl)      jr z,$+5      dec a      jr FNPLoop      inc l      ld a,(hl)      scf      ret

I made that to be a faster alternative to using a bcall

[Runer112]

Optimized a bit. The largest optimization was removing end checking, because it's impossible for an application not to have a number of pages field. I also optimized the search loop by rearranging it a bit to remove the unconditional jump.

Code: Select All | Copy To Clipboard

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

FindNumPages: ;Inputs: ;     The app base page is loaded in MemBank1 ;Outputs: ;     A, (HL) is the number of app pages      ld hl,4000h      ld a,81h      ld c,a FNPLoop:      dec a      cpir      inc a      cp (hl)      jr nz,FNPLoop      inc l      ld a,(hl)      ret

[thepenguin77]

There are actually rare cases where that routine could fail. Of course I would assume it will work 99.9% of apps, if someone changed the order of the header and put the time stamp key in front of the number of pages, it could theoretically contain $80, $81.

But, now that I think about it, this is so rare that it will never happen.

[calc84maniac]

Isn't that routine searching for $80, $81 anyway?

Edit: Oh, I see what you're saying. The time stamp data could contain $80, $81.

[NanoWar]

Has anybody got a good rectangle function? It should use variable width by pixel, not byte... Here's my ugly code:

Code: Select All | Copy To Clipboard

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132

rectangle ;inputs: l=Y, a=X, b=height, c=length ;save coords & stuff h, a push hl push bc call rectangle.calc ;below pop bc pop hl rectangle.display ; inputs: h=X, l=Y, b=height ld a, h ld e, l ld h, $00 ld d, h add hl, de add hl, de add hl, hl add hl, hl ;l*12 ld e, a srl e srl e srl e ;x/8 add hl, de ld de, gbuf add hl, de rectangle.display.loop: push bc push hl ld a, (hl) ld c, a ld a, (rectangle.scanline1) ; somewhere in ram... xor c ld (hl), a inc hl ld a, (rectangle.scanline2) or a jr z, rectangle.display.noloop2 ld b, a rectangle.display.loop2: ld a, (hl) xor $FF ld (hl), a inc hl djnz rectangle.display.loop2 rectangle.display.noloop2: ld a, (hl) ld c, a ld a, (rectangle.scanline3) xor c ld (hl), a pop hl pop bc ld de, 12 add hl, de djnz rectangle.display.loop ret rectangle.calc ;inputs: ; a = x ; b = height ; c = length ld d, a ld a, $FF ld (rectangle.scanline1), a xor a ld (rectangle.scanline2), a ld (rectangle.scanline3), a ld a, d and 7 ld d, a or a jr z, rectangle.skipShift1 ld e, $FF rectangle.shift1 srl e dec a or a jr nz, rectangle.shift1 ld a, e ld (rectangle.scanline1), a rectangle.skipShift1 ld a, d ; a = shift right ld h, a ; save add a, c ; a + c ld b, a ; save b = a + c and 7 ; /8 Rest? ld d, a ; Rest ld a, 8 sub d ; 8 - Rest ld d, a ; = d ld e, $FF rectangle.shift2 sla e dec a or a jr nz, rectangle.shift2 ld a, e ld (rectangle.scanline3), a ld a, 16 ld e, h ; a sub e ; 16 - a sub d ; -d srl a srl a srl a ld d, a ; ld a, c srl a srl a srl a ; /8 sub d ld d, a ld a, (rectangle.scanline2) add a, d ld (rectangle.scanline2), a ; ld a, b and %11111000 or a ; if (shift_right + length)<8, do (rectangle.scanline1 & rectangle.scanline3) ret nz ld a, (rectangle.scanline1) ld d, a ld a, (rectangle.scanline3) and d ld (rectangle.scanline1), a xor a ld (rectangle.scanline2), a ld (rectangle.scanline3), a ret

How bad is it?

[chickendude]

You can check out the MirageOS source, but i think it just draws four lines using their line routine.

[NanoWar]

Oh it should be a filled rect routine .

[Hayleia]

There is a filled rectangle routine in Axe. I don't know where you can see its source code though.

[deeph]

Here's one I use for one of my project :

Code: Select All | Copy To Clipboard

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134

;=======================================; ; Rectangle Filling Routine Version 1.0 ; ; By Jason Kovacs & The TCPA - 10/11/99 ; ;=======================================; ; Input:  D = Top Left X Coordinate, E = Top Left Y Coordinate ; H = Bottom Right X Coord,  L = Bottom Right Y Coord ; C = Color of Lines (0-White, 1-Black, 2-XORed) ; ; Output: A Rectangle is drawn to the Graph Buffer with its border ;    and everything within it Filled in according to the value in ;    reg C which specifies the Color. ; ; Registers Affected: AF Destroyed; B=0 ; C, DE, HL Preserved. ;    The Index Registers and the Shadow Registers Aren't Used. Rectangle_Filled: ld a,l sub e inc a ld b,a ld a,h sub d inc a    push de Rect_Fill_Loop: push af call V_Line pop af inc d dec a jr nz, Rect_Fill_Loop pop de ret ;=======================================; ; Horizontal and Verticle Line Routines ; ; By Jason Kovacs & The TCPA - 10/11/99 ; ;=======================================; ; For H_Line and V_Line: ; ; Input:  B = Length of Line (Number of Pixels) ; C = Color of Line (0-White, 1-Black, 2-XORed) ; D = X Coordinate Start of the Line ; E = Y Coordinate Start of the Line ; ; Output: Lines are Drawn to the Graph Buffer, and the Starting ;    Byte and Pixel Mask are Automatically determined according ;    to the Input of the Coordinates in DE. ; ; Registers Affected:  All Registers are Preserved Except AF. V_Line: push de push hl push bc ld a,d call Getpix pop bc push bc ld d,c ld c,a ld a,d ld de,12 or a call z,V_White_Line dec a call z,V_Black_Line dec a call z,V_XORed_Line pop bc pop hl pop de ret V_White_Line: ld a,c cpl ld c,a V_White_Line_2: ld a,(hl) and c ld (hl),a add hl,de djnz V_White_Line_2 xor a ret V_Black_Line: ld a,(hl) or c ld (hl),a add hl,de djnz V_Black_Line xor a ret V_XORed_Line: ld a,(hl) xor c ld (hl),a add hl,de djnz V_XORed_Line ret Getpix: ld d,0 ld h,d ld l,e add hl,de add hl,de add hl,hl add hl,hl ld de,plotsscreen add hl,de Getbit: ld b,0 ld c,a and %00000111 srl c srl c srl c add hl,bc ld b,a inc b ld a,%00000001 GBLoop: rrca djnz GBLoop ret

[NanoWar]

Ah cool thanks. This was a bit off topic I guess

[Xeda112358]

Here is a routine that I started a long time ago (back when I coded only in hex). I have been too lazy to replace the hex code with mnemonics, but it can draw all sorts of rectangle types I am sure it can be optimised, but it works:

(note, RectData needs to be 24 bytes of free ram. I typically use data in the op registers or cmdshadow, or something like that.)

Code: Select All | Copy To Clipboard

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323

DrawRectToGraph:      ld hl,9340h ;=============================================================== DrawRectToBuffer: DrawRect: ;=============================================================== ;Inputs: ;     A is the type of rectangle to draw ;        0 =White ;        1 =Black ;        2 =XOR ;        3 =Black border ;        4 =White border ;        5 =XOR border ;        6 =Black border, white inside ;        7 =Black border, XOR inside ;        8 =White border, black inside ;        9 =White border, XOR inside ;        10=Shift Up ;        11=Shift Down ; ; ;        14=pxlTestRect  (returns the number of on pixels in the rectangular region) ;        15=pxlTestBorder (returns the number of on pixels on the border, good for collision detection) ;     B is the height ;     C is the Y pixel coordinate ;     D is the width in pixels ;     E is is the X pixel coordinate ;===============================================================      di      push hl      pop ix      ex af,af' ;Check if coords are negative      ld a,c      or a      jp p,$+9        add a,b        ret nc        ret z        ld b,a        ld c,0      ld a,e      or a      jp p,$+9        add a,d        ret nc        ret z        ld d,a        ld e,0 ;Check dimensions      ld a,b      or a      ret z      jp p,$+6        neg        ld b,a      add a,c      sub 64      jr c,$+6        neg        add a,b        ld b,a      ld a,d      or a      ret z      jp p,$+6        neg        ld d,a      add a,e      sub 96      jr c,$+6        neg        add a,d        ld d,a      ld a,c      cp 64      ret nc      ld a,e      cp 96      ret nc MakePattern:      push bc      ld hl,RectData      ld b,24      xor a      ld (hl),a      inc l      djnz $-2      ld hl,RectData      ld c,RectData+12      ld a,e      sub 8      jr c,$+6        inc l        inc c        jr $-6      add a,8      ld e,a      ld b,a      inc b      ld a,d      add a,e      ld e,a      ld a,1      rrca      djnz $-1      ld b,l      push af      ld l,c      or (hl)      ld (hl),a      ld l,b      pop af      dec a      scf      adc a,a      ld (hl),a      ld a,e      sub 8      jr c,$+10      jr z,$+10        inc l        ld (hl),-1        inc c        jr $-10      add a,8      ld b,a      or a      ld a,1      jr z,$+5      rrca      djnz $-1      ld b,l      push af      ld l,c      or (hl)      ld (hl),a      ld l,b      pop af      dec a      cpl      and (hl)      ld (hl),a      pop bc      ld a,b      ld b,0      ld h,b      ld l,c      add hl,hl      add hl,bc      add hl,hl      add hl,hl      push ix      pop bc      add hl,bc      ld b,a      ex af,af'      .db $CB,$67,$28,$10,$D6,$10,$F5,$0E,$18,$11      .dw RectData      .db $1A,$2F,$12,$13,$0D,$20,$F9,$F1      or a      jr nz,$+13h      .db $0E,$0C,$11      .dw RectData      .db $1A,$2F,$A6,$77,$13,$23,$0D,$20,$F7,$10,$F0,$C9      dec a      jr nz,$+12h      .db $0E,$0C,$11      .dw RectData      .db $1A,$B6,$77,$13,$23,$0D,$20,$F8,$10,$F1,$C9      dec a      jr nz,$+12h      .db $0E,$0C,$11      .dw RectData      .db $1A,$AE,$77,$13,$23      .db $0D,$20,$F8,$10,$F1,$C9      dec a      jr nz,$+26h      .db $0E,$0C,$11      .dw RectData      .db $1A,$B6,$77,$13,$23,$0D,$20,$F8,$05,$C8      .db $05,$28,$0F,$0E,$0C,$11      .dw RectData+12      .db $1A,$B6,$77,$13,$23,$0D,$20,$F8,$10,$F1,$04,$18,$DC      dec a      jr nz,$+28h      .db $0E,$0C,$11      .dw RectData      .db $1A,$A6,$AE,$77,$13,$23,$0D,$20,$F7,$05,$C8,$05,$28,$10,$0E,$0C,$11      .dw RectData+12      .db $1A,$A6,$AE,$77,$13,$23,$0D,$20,$F7,$10,$F0,$04,$18,$DA      dec a      jr nz,$+26h      .db $0E,$0C,$11      .dw RectData      .db $1A,$AE      .db $77,$13,$23,$0D,$20,$F8,$05,$C8,$05,$28,$0F,$0E,$0C,$11      .dw RectData+12      .db $1A,$AE,$77,$13,$23,$0D,$20,$F8      .db $10,$F1,$04,$18,$DC      dec a      jr nz,$+36h      .db $0E,$0C,$11      .dw RectData      .db $1A,$B6,$77,$13,$23,$0D,$20,$F8,$05,$C8,$05      .db $28,$1F,$E5,$0E,$0C,$11      .dw RectData      .db $1A,$A6,$AE,$77,$13,$23,$0D,$20,$F7,$E1,$0E,$0C,$11      .dw RectData+12      .db $1A      .db $B6,$77,$13,$23,$0D,$20,$F8,$10,$E1,$04,$18,$CC      .db $3D,$20,$33,$0E,$0C,$11      .dw RectData      .db $1A,$B6,$77,$13      .db $23,$0D,$20,$F8,$05,$C8,$05,$28,$1E,$E5,$0E,$0C,$11      .dw RectData      .db $1A,$AE,$77,$13,$23,$0D,$20,$F8,$E1      .db $0E,$0C,$11      .dw RectData+12      .db $1A,$B6,$77,$13,$23,$0D,$20,$F8,$10,$E2,$04,$18,$CD,$3D,$20,$34,$0E,$0C,$11      .dw RectData      .db $1A,$A6,$AE,$77,$13,$23,$0D,$20,$F7,$05,$C8,$05,$28,$1E,$E5,$0E,$0C,$11      .dw RectData      .db $1A,$B6      .db $77,$13,$23,$0D,$20,$F8,$E1,$0E,$0C,$11      .dw RectData+12      .db $1A,$AE,$77,$13,$23,$0D,$20,$F8,$10,$E2,$04,$18      .db $CC,$3D,$20,$35,$0E,$0C,$11      .dw RectData      .db $1A,$A6,$AE,$77,$13,$23,$0D,$20,$F7,$05,$C8,$05,$28,$1F,$E5      .db $0E,$0C,$11      .dw RectData      .db $1A,$AE,$77,$13,$23,$0D,$20,$F8,$E1,$0E,$0C,$11      .dw RectData+12      .db $1A,$A6,$AE,$77,$13      .db $23,$0D,$20,$F7,$10,$E1,$04,$18,$CB,$3D,$20,$37,$05,$C8,$F3,$E5,$D9,$01,$0C,$00,$E1,$09,$D9,$0E      .db $0C,$11      .dw RectData      .db $D5,$D9,$D1,$D9,$1A,$2F,$A6,$D9,$47,$1A,$A6,$B0,$13,$23,$D9,$77,$13,$23,$0D,$20      .db $EF,$10,$E4,$0E,$0C,$11      .dw RectData      .db $1A,$2F,$A6,$77,$13,$23,$0D,$20,$F7,$FB,$C9      .db $3D,$20,$40,$F3,$C5      .db $11,$0C,$00,$19,$10,$FD,$2B,$E5,$D9,$11,$F4,$FF,$E1,$19,$D9,$C1,$05,$C8,$0E,$0C,$11      .dw RectData+11      .db $D5      .db $D9,$D1,$D9,$1A,$2F,$A6,$D9,$47,$1A,$A6,$B0,$1B,$2B,$D9,$77,$1B,$2B,$0D,$20,$EF,$10,$E4,$0E,$0C      .db $11      .dw RectData+11      .db $1A,$2F,$A6,$77,$1B,$2B,$0D,$20,$F7,$FB,$C9      dec a      ret z      dec a      ret z      exx      ld de,0      ld c,8      exx PxlTestRect:      dec a      jr nz,PxlTestBorder      ld c,12      ld de,RectData PxlTstRectLoop:        call PxlTestWithMask        djnz PxlTstRectLoop-5        exx ;DE contains the number of pixels        ret PxlTestBorder:      dec a      ret nz      ld c,12      ld de,RectData      call PxlTestWithMask      dec b      jr z,PxlTestBorder-4      dec b      jr z,PxlTestBrdrEnd      ld c,12      ld de,RectData+12 PxlTstBrdrLoop:        call PxlTestWithMask        djnz PxlTstBrdrLoop-5 PxlTestBrdrEnd:      ld de,RectData      ld c,12      call PxlTestWithMask      exx ;DE contains the number of on pixels        ret PxlTestWithMask:      ld a,(de)      and (hl)      exx      ld b,c      add a,a      jr nc,$+3      inc de      jr z,$+4      djnz $-6      exx      inc de      inc hl      dec c      jr nz,PxlTestWithMask      ret