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update:nes_branch
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@Dozingfiretruck
Dozingfiretruck committed Jul 12, 2024
1 parent d77c6cf commit d08bd9f
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Showing 2 changed files with 62 additions and 54 deletions.
55 changes: 31 additions & 24 deletions src/nes.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -44,10 +44,10 @@ int nes_deinit(nes_t *nes){
extern nes_color_t nes_palette[];

static inline void nes_palette_generate(nes_t* nes){
for (size_t i = 0; i < 32; i++) {
for (uint8_t i = 0; i < 32; i++) {
nes->nes_ppu.palette[i] = nes_palette[nes->nes_ppu.palette_indexes[i]];
}
for (size_t i = 1; i < 8; i++){
for (uint8_t i = 1; i < 8; i++){
nes->nes_ppu.palette[4 * i] = nes->nes_ppu.palette[0];
}
}
Expand All @@ -60,12 +60,12 @@ static void nes_render_background_line(nes_t* nes,uint16_t scanline,nes_color_t*
const uint8_t tile_y = (const uint8_t)nes->nes_ppu.v.coarse_y;
uint8_t nametable_id = (uint8_t)nes->nes_ppu.v.nametable;
for (uint8_t tile_x = dx; tile_x < 32; tile_x++){
uint32_t pattern_id = nes->nes_ppu.name_table[nametable_id][tile_x + (tile_y << 5)];
const uint32_t pattern_id = nes->nes_ppu.name_table[nametable_id][tile_x + (tile_y << 5)];
const uint8_t* bit0_p = nes->nes_ppu.pattern_table[nes->nes_ppu.CTRL_B ? 4 : 0] + pattern_id * 16;
const uint8_t* bit1_p = bit0_p + 8;
const uint8_t bit0 = bit0_p[dy];
const uint8_t bit1 = bit1_p[dy];
uint8_t attribute = nes->nes_ppu.name_table[nametable_id][960 + ((tile_y >> 2) << 3) + (tile_x >> 2)];
const uint8_t attribute = nes->nes_ppu.name_table[nametable_id][960 + ((tile_y >> 2) << 3) + (tile_x >> 2)];
// 1:D4-D5/D6-D7 0:D0-D1/D2-D3
// 1:D2-D3/D6-D7 0:D0-D1/D4-D5
const uint8_t high_bit = ((attribute >> (((tile_y & 2) << 1) | (tile_x & 2))) & 3) << 2;
Expand All @@ -78,12 +78,12 @@ static void nes_render_background_line(nes_t* nes,uint16_t scanline,nes_color_t*
}
nametable_id ^= nes->nes_rom.mirroring_type ? 1:2;
for (uint8_t tile_x = 0; tile_x <= dx; tile_x++){
uint32_t pattern_id = nes->nes_ppu.name_table[nametable_id][tile_x + (tile_y << 5)];
const uint32_t pattern_id = nes->nes_ppu.name_table[nametable_id][tile_x + (tile_y << 5)];
const uint8_t* bit0_p = nes->nes_ppu.pattern_table[nes->nes_ppu.CTRL_B ? 4 : 0] + pattern_id * 16;
const uint8_t* bit1_p = bit0_p + 8;
const uint8_t bit0 = bit0_p[dy];
const uint8_t bit1 = bit1_p[dy];
uint8_t attribute = nes->nes_ppu.name_table[nametable_id][960 + ((tile_y >> 2) << 3) + (tile_x >> 2)];
const uint8_t attribute = nes->nes_ppu.name_table[nametable_id][960 + ((tile_y >> 2) << 3) + (tile_x >> 2)];
// 1:D4-D5/D6-D7 0:D0-D1/D2-D3
// 1:D2-D3/D6-D7 0:D0-D1/D4-D5
const uint8_t high_bit = ((attribute >> (((tile_y & 2) << 1) | (tile_x & 2))) & 3) << 2;
Expand All @@ -95,18 +95,18 @@ static void nes_render_background_line(nes_t* nes,uint16_t scanline,nes_color_t*
break;
}
for (; m >= skew; m--){
uint8_t low_bit = ((bit0 >> m) & 0x01) | ((bit1 >> m)<<1 & 0x02);
uint8_t palette_index = (high_bit & 0x0c) | low_bit;
const uint8_t low_bit = ((bit0 >> m) & 0x01) | ((bit1 >> m)<<1 & 0x02);
const uint8_t palette_index = (high_bit & 0x0c) | low_bit;
draw_data[p++] = nes->nes_ppu.background_palette[palette_index];
}
m = 7;
}
}

static void nes_render_sprite_line(nes_t* nes,uint16_t scanline,nes_color_t* draw_data){
nes_color_t background_color = nes->nes_ppu.background_palette[0];
const nes_color_t background_color = nes->nes_ppu.background_palette[0];
uint8_t sprite_number = 0;
uint8_t sprite_size = nes->nes_ppu.CTRL_H?16:8;
const uint8_t sprite_size = nes->nes_ppu.CTRL_H?16:8;

for (uint8_t i = 63; i > 0 ; i--){
if (nes->nes_ppu.sprite_info[i].y >= 0xEF){
Expand Down Expand Up @@ -156,8 +156,8 @@ static void nes_render_sprite_line(nes_t* nes,uint16_t scanline,nes_color_t* dra
uint8_t p = nes->nes_ppu.sprite_info[i].x;
if (nes->nes_ppu.sprite_info[i].flip_h){
for (int8_t m = 0; m <= 7; m++){
uint8_t low_bit = ((sprite_bit0 >> m) & 0x01) | ((sprite_bit1 >> m)<<1 & 0x02);
uint8_t palette_index = (nes->nes_ppu.sprite_info[i].sprite_palette << 2) | low_bit;
const uint8_t low_bit = ((sprite_bit0 >> m) & 0x01) | ((sprite_bit1 >> m)<<1 & 0x02);
const uint8_t palette_index = (nes->nes_ppu.sprite_info[i].sprite_palette << 2) | low_bit;
if (palette_index%4 != 0){
if (nes->nes_ppu.sprite_info[i].priority){
if (draw_data[p] == background_color){
Expand All @@ -173,8 +173,8 @@ static void nes_render_sprite_line(nes_t* nes,uint16_t scanline,nes_color_t* dra
}
}else{
for (int8_t m = 7; m >= 0; m--){
uint8_t low_bit = ((sprite_bit0 >> m) & 0x01) | ((sprite_bit1 >> m)<<1 & 0x02);
uint8_t palette_index = (nes->nes_ppu.sprite_info[i].sprite_palette << 2) | low_bit;
const uint8_t low_bit = ((sprite_bit0 >> m) & 0x01) | ((sprite_bit1 >> m)<<1 & 0x02);
const uint8_t palette_index = (nes->nes_ppu.sprite_info[i].sprite_palette << 2) | low_bit;
if (palette_index%4 != 0){
if (nes->nes_ppu.sprite_info[i].priority){
if (draw_data[p] == background_color){
Expand All @@ -191,10 +191,9 @@ static void nes_render_sprite_line(nes_t* nes,uint16_t scanline,nes_color_t* dra
}
}
sprite0:
// sprite 0
if (nes->nes_ppu.sprite_info[0].y >= 0xEF)
return;
uint8_t sprite_y = (uint8_t)(nes->nes_ppu.sprite_info[0].y + 1);
const uint8_t sprite_y = (uint8_t)(nes->nes_ppu.sprite_info[0].y + 1);
if (scanline < sprite_y || scanline >= sprite_y + sprite_size)
return;
sprite_number ++;
Expand Down Expand Up @@ -235,13 +234,13 @@ static void nes_render_sprite_line(nes_t* nes,uint16_t scanline,nes_color_t* dra

const uint8_t sprite_date = sprite_bit0 | sprite_bit1;
if (sprite_date && nes->nes_ppu.MASK_b && nes->nes_ppu.STATUS_S == 0){
uint8_t nametable_id = (uint8_t)nes->nes_ppu.v.nametable;
const uint8_t nametable_id = (uint8_t)nes->nes_ppu.v.nametable;
const uint8_t tile_x = (nes->nes_ppu.sprite_info[0].x) >> 3;
const uint8_t tile_y = scanline >> 3;
uint32_t pattern_id = nes->nes_ppu.name_table[nametable_id][tile_x + (tile_y << 5)];
const uint32_t pattern_id = nes->nes_ppu.name_table[nametable_id][tile_x + (tile_y << 5)];
const uint8_t* bit0_p = nes->nes_ppu.pattern_table[nes->nes_ppu.CTRL_B ? 4 : 0] + pattern_id * 16;
const uint8_t* bit1_p = bit0_p + 8;
uint8_t background_date = bit0_p[dy] | bit1_p[dy]<<1;
const uint8_t background_date = bit0_p[dy] | bit1_p[dy]<<1;
if (sprite_date == background_date){
nes->nes_ppu.STATUS_S = 1;
}
Expand All @@ -253,8 +252,8 @@ static void nes_render_sprite_line(nes_t* nes,uint16_t scanline,nes_color_t* dra
uint8_t p = nes->nes_ppu.sprite_info[0].x;
if (nes->nes_ppu.sprite_info[0].flip_h){
for (int8_t m = 0; m <= 7; m++){
uint8_t low_bit = ((sprite_bit0 >> m) & 0x01) | ((sprite_bit1 >> m)<<1 & 0x02);
uint8_t palette_index = (nes->nes_ppu.sprite_info[0].sprite_palette << 2) | low_bit;
const uint8_t low_bit = ((sprite_bit0 >> m) & 0x01) | ((sprite_bit1 >> m)<<1 & 0x02);
const uint8_t palette_index = (nes->nes_ppu.sprite_info[0].sprite_palette << 2) | low_bit;
if (palette_index%4 != 0){
if (nes->nes_ppu.sprite_info[0].priority){
if (draw_data[p] == background_color){
Expand All @@ -270,8 +269,8 @@ static void nes_render_sprite_line(nes_t* nes,uint16_t scanline,nes_color_t* dra
}
}else{
for (int8_t m = 7; m >= 0; m--){
uint8_t low_bit = ((sprite_bit0 >> m) & 0x01) | ((sprite_bit1 >> m)<<1 & 0x02);
uint8_t palette_index = (nes->nes_ppu.sprite_info[0].sprite_palette << 2) | low_bit;
const uint8_t low_bit = ((sprite_bit0 >> m) & 0x01) | ((sprite_bit1 >> m)<<1 & 0x02);
const uint8_t palette_index = (nes->nes_ppu.sprite_info[0].sprite_palette << 2) | low_bit;
if (palette_index%4 != 0){
if (nes->nes_ppu.sprite_info[0].priority){
if (draw_data[p] == background_color){
Expand All @@ -288,6 +287,7 @@ static void nes_render_sprite_line(nes_t* nes,uint16_t scanline,nes_color_t* dra
}
}

// https://www.nesdev.org/wiki/PPU_rendering

void nes_run(nes_t* nes){
nes_printf("mapper:%03d\n",nes->nes_rom.mapper_number);
Expand Down Expand Up @@ -320,6 +320,7 @@ void nes_run(nes_t* nes){
#if (NES_ENABLE_SOUND==1)
nes_apu_frame(nes);
#endif
// https://www.nesdev.org/wiki/PPU_rendering#Visible_scanlines_(0-239)
for(scanline = 0; scanline < NES_HEIGHT; scanline++) { // 0-239 Visible frame
if (nes->nes_ppu.MASK_b){
#if (NES_RAM_LACK == 1)
Expand All @@ -335,8 +336,10 @@ void nes_run(nes_t* nes){
nes_render_sprite_line(nes,scanline,nes->nes_draw_data + scanline * NES_WIDTH);
#endif
}
nes_opcode(nes,NES_PPU_CPU_CLOCKS);
nes_opcode(nes,85); // ppu cycles: 85*3=255
// https://www.nesdev.org/wiki/PPU_scrolling#Wrapping_around
if (nes->nes_ppu.MASK_b){
// https://www.nesdev.org/wiki/PPU_scrolling#At_dot_256_of_each_scanline
if ((nes->nes_ppu.v.fine_y) < 7) {
nes->nes_ppu.v.fine_y++;
}else {
Expand All @@ -352,9 +355,11 @@ void nes_run(nes_t* nes){
}
nes->nes_ppu.v.coarse_y = y;
}
// https://www.nesdev.org/wiki/PPU_scrolling#At_dot_257_of_each_scanline
// v: ....A.. ...BCDEF <- t: ....A.. ...BCDEF
nes->nes_ppu.v_reg = (nes->nes_ppu.v_reg & (uint16_t)0xFBE0) | (nes->nes_ppu.t_reg & (uint16_t)0x041F);
}
nes_opcode(nes,NES_PPU_CPU_CLOCKS-85);
#if (NES_ENABLE_SOUND==1)
if (scanline % 66 == 65) nes_apu_frame(nes);
#endif
Expand Down Expand Up @@ -384,9 +389,11 @@ void nes_run(nes_t* nes){
}

nes->nes_ppu.ppu_status &= 0x10; // Clear:VBlank,Sprite 0,Overflow
// nes->nes_ppu.ppu_status = 0;
nes_opcode(nes,NES_PPU_CPU_CLOCKS); // 261 Pre-render line
//do more
if (nes->nes_ppu.MASK_b){
// https://www.nesdev.org/wiki/PPU_scrolling#During_dots_280_to_304_of_the_pre-render_scanline_(end_of_vblank)
// v: GHIA.BC DEF..... <- t: GHIA.BC DEF.....
nes->nes_ppu.v_reg = (nes->nes_ppu.v_reg & (uint16_t)0x841F) | (nes->nes_ppu.t_reg & (uint16_t)0x7BE0);
}
Expand Down
61 changes: 31 additions & 30 deletions src/nes_cpu.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -708,9 +708,9 @@ static void nes_php(nes_t* nes){

// Jump/Flag commands:

static inline void nes_branch(nes_t* nes) {
static inline void nes_branch(nes_t* nes,const uint16_t address) {
const uint16_t pc_old = nes->nes_cpu.PC;
nes->nes_cpu.PC = nes_opcode_table[nes->nes_cpu.opcode].addressing_mode(nes);
nes->nes_cpu.PC = address;
nes->nes_cpu.cycles++;
nes->nes_cpu.cycles += ((nes->nes_cpu.PC ^ pc_old) >> 8)?1:0;
}
Expand All @@ -721,10 +721,10 @@ static inline void nes_branch(nes_t* nes) {
*/
static void nes_bpl(nes_t* nes){
const uint16_t address = nes_opcode_table[nes->nes_cpu.opcode].addressing_mode(nes);
if (nes->nes_cpu.N==0){
nes_branch(nes);
}
else nes->nes_cpu.PC++;
nes_branch(nes,address);
}
}

/*
Expand All @@ -733,10 +733,10 @@ static void nes_bpl(nes_t* nes){
*/
static void nes_bmi(nes_t* nes){
const uint16_t address = nes_opcode_table[nes->nes_cpu.opcode].addressing_mode(nes);
if (nes->nes_cpu.N){
nes_branch(nes);
nes_branch(nes,address);
}
else nes->nes_cpu.PC++;
}

/*
Expand All @@ -745,10 +745,10 @@ static void nes_bmi(nes_t* nes){
*/
static void nes_bvc(nes_t* nes){
const uint16_t address = nes_opcode_table[nes->nes_cpu.opcode].addressing_mode(nes);
if (nes->nes_cpu.V==0){
nes_branch(nes);
nes_branch(nes,address);
}
else nes->nes_cpu.PC++;
}

/*
Expand All @@ -757,10 +757,10 @@ static void nes_bvc(nes_t* nes){
*/
static void nes_bvs(nes_t* nes){
const uint16_t address = nes_opcode_table[nes->nes_cpu.opcode].addressing_mode(nes);
if (nes->nes_cpu.V){
nes_branch(nes);
nes_branch(nes,address);
}
else nes->nes_cpu.PC++;
}

/*
Expand All @@ -769,10 +769,10 @@ static void nes_bvs(nes_t* nes){
*/
static void nes_bcc(nes_t* nes){
const uint16_t address = nes_opcode_table[nes->nes_cpu.opcode].addressing_mode(nes);
if (nes->nes_cpu.C==0){
nes_branch(nes);
nes_branch(nes,address);
}
else nes->nes_cpu.PC++;
}

/*
Expand All @@ -781,10 +781,10 @@ static void nes_bcc(nes_t* nes){
*/
static void nes_bcs(nes_t* nes){
const uint16_t address = nes_opcode_table[nes->nes_cpu.opcode].addressing_mode(nes);
if (nes->nes_cpu.C){
nes_branch(nes);
nes_branch(nes,address);
}
else nes->nes_cpu.PC++;
}

/*
Expand All @@ -793,10 +793,10 @@ static void nes_bcs(nes_t* nes){
*/
static void nes_bne(nes_t* nes){
const uint16_t address = nes_opcode_table[nes->nes_cpu.opcode].addressing_mode(nes);
if (nes->nes_cpu.Z==0){
nes_branch(nes);
nes_branch(nes,address);
}
else nes->nes_cpu.PC++;
}

/*
Expand All @@ -805,10 +805,10 @@ static void nes_bne(nes_t* nes){
*/
static void nes_beq(nes_t* nes){
const uint16_t address = nes_opcode_table[nes->nes_cpu.opcode].addressing_mode(nes);
if (nes->nes_cpu.Z){
nes_branch(nes);
nes_branch(nes,address);
}
else nes->nes_cpu.PC++;
}

/*
Expand Down Expand Up @@ -1019,26 +1019,25 @@ static void nes_sre(nes_t* nes){
NES_CHECK_Z(nes->nes_cpu.A);
}

/*---------
/*
{adr}:={adr}ror A:=A adc {adr}
N V U B D I Z C
* * * *
*/
static void nes_rra(nes_t* nes){
uint16_t address = nes_opcode_table[nes->nes_cpu.opcode].addressing_mode(nes);
uint8_t saveflags=nes->nes_cpu.C;
uint16_t data = nes_read_cpu(nes,address);
nes->nes_cpu.P= (nes->nes_cpu.P & 0xfe) | (data & 0x01);
// ror
data |= (nes->nes_cpu.C << 8);
uint8_t cflag = data & 0x01;
data >>= 1;
if (saveflags) data |= 0x80;
nes_write_cpu(nes,address,data);

const uint16_t result16 = nes->nes_cpu.A + data + nes->nes_cpu.C;
nes->nes_cpu.C = result16 >> 8;
const uint8_t result8 = (uint8_t)result16;
if (!((nes->nes_cpu.A ^ data) & 0x80) && ((nes->nes_cpu.A ^ result8) & 0x80)) nes->nes_cpu.V = 1;
nes_write_cpu(nes,address,(uint8_t)data);
// adc
const uint16_t data1 = nes->nes_cpu.A + data + cflag;
nes->nes_cpu.C = data1 >> 8;
if (!((nes->nes_cpu.A ^ data) & 0x80) && ((nes->nes_cpu.A ^ (uint8_t)data1) & 0x80)) nes->nes_cpu.V = 1;
else nes->nes_cpu.V = 0;
nes->nes_cpu.A = result8;
nes->nes_cpu.A = (uint8_t)data1;
NES_CHECK_N(nes->nes_cpu.A);
NES_CHECK_Z(nes->nes_cpu.A);
}
Expand Down Expand Up @@ -1567,6 +1566,8 @@ void nes_opcode(nes_t* nes,uint16_t ticks){
fprintf(debug_fp,"PC: 0x%04X cycles:%lld \n", nes->nes_cpu.PC,cycles);
if (cycles == 56955){
printf("cycles");
printf("cycles");
printf("cycles");
}

cycles_old = nes->nes_cpu.cycles;
Expand Down

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