tfv: more optimization, move SCREEN_X to register X
This commit is contained in:
Vince Weaver
parent
5cee1db0b1
commit
4d86457d96
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@ -109,16 +109,14 @@ struct cycle_counts {
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int put_sprite;
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} cycles;
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static int last_color=0,last_xx=0,last_yy=0;
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static int lookup_map(int xx, int yy) {
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int color,offset;
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last_xx=xx;
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ram[LAST_SPACEX_I]=xx;
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xx=xx&MASK_X;
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last_yy=yy;
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ram[LAST_SPACEY_I]=yy;
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yy=yy&MASK_Y;
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@ -132,7 +130,7 @@ static int lookup_map(int xx, int yy) {
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offset=yy<<3;
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offset+=xx;
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cycles.lookup_map+=37;
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cycles.lookup_map+=39;
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if ((yy>7) || (xx>7)) {
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cycles.lookup_map+=14;
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@ -156,8 +154,8 @@ static int lookup_map(int xx, int yy) {
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update_cache:
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cycles.lookup_map+=9;
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last_color=color;
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cycles.lookup_map+=10;
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ram[LAST_MAP_COLOR]=color;
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return color;
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}
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@ -789,29 +787,18 @@ static void draw_background_mode7(void) {
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fixed_add(ram[SPACEY_I],ram[SPACEY_F],
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ram[TEMP_I],ram[TEMP_F],
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&ram[SPACEY_I],&ram[SPACEY_F]);
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cycles.mode7+=25;
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cycles.mode7+=22;
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if (!displayed) {
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printf("SPACEY! %x:%x\n",ram[SPACEY_I],ram[SPACEY_F]);
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}
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// go through all points in this screen line
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for (ram[SCREEN_X] = 0;
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ram[SCREEN_X] < LOWRES_W;
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ram[SCREEN_X]++) {
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ram[SCREEN_X] = 0;
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while(1) {
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// get a pixel from the tile and put it on the screen
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/* cache last value */
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cycles.mode7+=9;
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if (ram[SPACEY_I]==last_yy) {
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cycles.mode7+=8;
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if (ram[SPACEX_I]==last_xx) {
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cycles.mode7+=6;
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map_color=last_color;
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goto match;
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}
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}
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nomatch:
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map_color=lookup_map(ram[SPACEX_I],ram[SPACEY_I]);
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cycles.mode7+=6;
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match:
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@ -839,7 +826,24 @@ match:
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fixed_add(ram[SPACEY_I],ram[SPACEY_F],
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ram[DY_I],ram[DY_F],
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&ram[SPACEY_I],&ram[SPACEY_F]);
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cycles.mode7+=49;
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ram[SCREEN_X]++;
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if (ram[SCREEN_X] >= LOWRES_W) break;
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cycles.mode7+=43;
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/* cache last value */
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cycles.mode7+=8;
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if (ram[SPACEY_I]==ram[LAST_SPACEY_I]) {
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cycles.mode7+=7;
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if (ram[SPACEX_I]==ram[LAST_SPACEX_I]) {
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cycles.mode7+=4;
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map_color=ram[LAST_MAP_COLOR];
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goto match;
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}
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}
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goto nomatch;
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}
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ram[SCREEN_Y]+=1;
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@ -146,5 +146,17 @@ Add some self-modifying code to inner loop:
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Total = 205,761
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Frame Rate = 4.86 fps
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More self-modifying code, also move SCREEN_X to X register
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Cycles: flying= 187
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Cycles: getkey= 46
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Cycles: page_flip= 26
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Cycles: multiply= 49,613
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Cycles: mode7= 118,034
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Cycles: lookup_map= 22,747
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Cycles: put_sprite= 2,561
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================================
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Total = 193,214
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Frame Rate = 5.18 fps
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32*40=12800
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Each cycle removed from inner X loop saves
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32*40=1280 cycles
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@ -919,7 +919,7 @@ odd_branch:
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;==========
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; 28
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clc ; fixed_add(&space_y,&temp,&space_y); ; 2
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clc ; fixed_add(&space_y,&temp,&space_y); ; 2
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lda SPACEY_F ; 3
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; adc TEMP_F ;
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adc RESULT+1 ; 3
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@ -931,23 +931,12 @@ odd_branch:
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; brk ; space_y = f7:04
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lda #0 ; 2
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sta SCREEN_X ; 3
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ldx #0 ; was SCREEN_X ; 2
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;==========
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; 25
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; 22
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screenx_loop:
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; cache color and return if same as last time
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lda SPACEY_I ; 3
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cmp LAST_SPACEY_I ; 3
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bne nomatch ; 2nt/3
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lda SPACEX_I ; 3
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cmp LAST_SPACEX_I ; 3
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bne nomatch ; 2nt/3
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lda LAST_MAP_COLOR ; 3
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jmp match ; 3
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;===========
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; 22
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nomatch:
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; do a full lookup, takes much longer
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jsr lookup_map ; get color in A ; 6
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@ -1000,13 +989,29 @@ dyi_label:
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adc #0 ; 2
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sta SPACEY_I ; 3
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inc SCREEN_X ; 5
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lda SCREEN_X ; 3
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cmp #40 ; LOWRES width ; 2
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bne screenx_loop ; 2nt/3
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inx ;inc SCREEN_X ; 2
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cpx #40 ; LOWRES width ; 2
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beq done_screenx_loop ; 2nt/3
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;=============
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; 49
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; 43
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; cache color and return if same as last time
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lda SPACEY_I ; 3
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spacey_label:
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cmp #0 ; LAST_SPACEY_I ; 2
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bne nomatch ; 2nt/3
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lda SPACEX_I ; 3
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spacex_label:
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cmp #0 ; LAST_SPACEX_I ; 2
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bne nomatch ; 2nt/3
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map_color_label:
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lda #0 ; LAST_MAP_COLOR ; 2
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jmp match ; 3
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;===========
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; max 19
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done_screenx_loop:
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inc SCREEN_Y ; 5
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lda SCREEN_Y ; 3
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cmp #40 ; LOWRES height ; 2
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@ -1041,13 +1046,13 @@ lookup_map:
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;nomatch:
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lda SPACEX_I ; 3
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;nomatch2:
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sta LAST_SPACEX_I ; 3
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sta spacex_label+1 ; LAST_SPACEX_I ; 4
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and #CONST_MAP_MASK_X ; 2
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sta SPACEX_I ; 3
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tay ; 2
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lda SPACEY_I ; 3
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sta LAST_SPACEY_I ; 3
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sta spacey_label+1 ; LAST_SPACEY_I ; 4
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and #CONST_MAP_MASK_Y ; wrap to 64x64 grid ; 2
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sta SPACEY_I ; 3
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@ -1062,7 +1067,7 @@ lookup_map:
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; SPACEX_I is in y
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cpy #$8 ; 2
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;============
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; 37
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; 39
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bcs ocean_color ; bgt 8 ;^2nt/3
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ldy SPACEY_I ; 3
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@ -1080,7 +1085,7 @@ ocean_color:
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lda water_map,Y ; the color of the sea ; 4
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update_cache:
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sta LAST_MAP_COLOR ; 3
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sta map_color_label+1 ; self-modifying ; 4
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rts ; 6
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flying_map:
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