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Improve portability and multiple fixes #13

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Improve portability and multiple fixes #13

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c1b785a
Makefile: simplify and use pkg-config for SDL2
deltabeard Feb 12, 2024
20a3f90
main: use SDL functions only
deltabeard Feb 12, 2024
8d8de02
main: add frame timing
deltabeard Feb 12, 2024
e8ed8be
main: use SDL instead of inttypes.h
deltabeard Feb 12, 2024
dca3c4e
main: center window & misc changes
deltabeard Feb 12, 2024
9e58632
main: fix running too fast when vsync off
deltabeard Feb 12, 2024
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9 changes: 6 additions & 3 deletions Makefile
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Original file line number Diff line number Diff line change
@@ -1,8 +1,11 @@
pokegb: pokegb.cc
$(CC) -O2 -Wall -Wno-return-type -Wno-misleading-indentation -Wno-parentheses -o $@ $< -lSDL2
CXXFLAGS := -Os -s -Wall -Wno-return-type -Wno-misleading-indentation -Wno-parentheses
override CXXFLAGS += $(shell pkg-config sdl2 --cflags)
override LDLIBS += $(shell pkg-config sdl2 --libs)

all: pokegb deobfuscated

rom.sav: empty.sav
cp $< $@

clean:
rm -f pokegb rom.sav
$(RM) pokegb rom.sav
79 changes: 42 additions & 37 deletions deobfuscated.cc
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Original file line number Diff line number Diff line change
@@ -1,8 +1,4 @@
#include <SDL2/SDL.h>
#include <cstdint>
#include <fcntl.h>
#include <sys/mman.h>
#include <unistd.h>
#include "SDL.h"

#define OPCREL(_) opcrel = (opcode - _) / 8

Expand All @@ -28,27 +24,29 @@
#define OP9_IMM_PTR(_) \
OP8_REL(_) case _ + 70 : operand = opcode & 64 ? mem8(PC++) : tmp8;

uint8_t opcode, opcrel, tmp8, operand, carry, neg, *rom0, *rom1, io[512],
Uint8 opcode, opcrel, tmp8, operand, carry, neg, *rom0, *rom1, io[512],
video_ram[8192], work_ram[16384], *extram, *extrambank,
reg8[] = {19, 0, 216, 0, 77, 1, 176, 1}, &F = reg8[6], &A = reg8[7],
*reg8_group[] = {reg8 + 1, reg8, reg8 + 3, reg8 + 2,
reg8 + 5, reg8 + 4, &F, &A},
&IF = io[271], &LCDC = io[320], &LY = io[324], IME, halt;

uint8_t const *key_state;
Uint8 const *key_state;

uint16_t PC = 256, *reg16 = (uint16_t *)reg8, &HL = reg16[2], SP = 65534,
&DIV = (uint16_t &)io[259], ppu_dot = 32,
Uint16 PC = 256, *reg16 = (Uint16 *)reg8, &HL = reg16[2], SP = 65534,
&DIV = (Uint16 &)io[259], ppu_dot = 32,
*reg16_group1[] = {reg16, reg16 + 1, &HL, &SP},
*reg16_group2[] = {reg16, reg16 + 1, &HL, &HL}, prev_cycles, cycles;

int tmp, tmp2, F_mask[] = {128, 128, 16, 16}, frame_buffer[23040],
int tmp, delay, F_mask[] = {128, 128, 16, 16}, frame_buffer[23040],
palette[] = {-1, -23197, -65536, -1 << 24,
-1, -8092417, -12961132, -1 << 24};
double comp;
Uint64 ot, nt;

void tick() { cycles += 4; }

uint8_t mem8(uint16_t addr = HL, uint8_t val = 0, int write = 0) {
Uint8 mem8(Uint16 addr = HL, Uint8 val = 0, int write = 0) {
tick();
switch (addr >> 13) {
case 1:
Expand Down Expand Up @@ -110,50 +108,46 @@ uint8_t mem8(uint16_t addr = HL, uint8_t val = 0, int write = 0) {
}
}

void set_flags(uint8_t mask, int Z, int N, int H, int C) {
void set_flags(Uint8 mask, int Z, int N, int H, int C) {
F = F & mask | !Z << 7 | N << 6 | H << 5 | C << 4;
}

uint16_t read16(uint16_t &addr = PC) {
Uint16 read16(Uint16 &addr = PC) {
tmp8 = mem8(addr++);
return mem8(addr++) << 8 | tmp8;
}

void push(uint16_t val) {
void push(Uint16 val) {
mem8(--SP, val >> 8, 1);
mem8(--SP, val, 1);
tick();
}

uint8_t reg8_access(uint8_t val, int write = 1, uint8_t o = opcrel) {
Uint8 reg8_access(Uint8 val, int write = 1, Uint8 o = opcrel) {
return (o &= 7) == 6 ? mem8(HL, val, write)
: write ? *reg8_group[o] = val
: *reg8_group[o];
}

uint8_t get_color(int tile, int y_offset, int x_offset) {
uint8_t *tile_data = &video_ram[tile * 16 + y_offset * 2];
Uint8 get_color(int tile, int y_offset, int x_offset) {
Uint8 *tile_data = &video_ram[tile * 16 + y_offset * 2];
return (tile_data[1] >> x_offset) % 2 * 2 + (*tile_data >> x_offset) % 2;
}

int main() {
rom1 = (rom0 = (uint8_t *)mmap(0, 1 << 20, PROT_READ, MAP_SHARED,
open("rom.gb", O_RDONLY), 0)) +
32768;
tmp = open("rom.sav", O_CREAT|O_RDWR, 0666);
ftruncate(tmp, 32768);
extrambank = extram =
(uint8_t *)mmap(0, 32768, PROT_READ | PROT_WRITE, MAP_SHARED, tmp, 0);
int main(int, char**) {
rom1 = (rom0 = (Uint8 *)SDL_LoadFile("rom.gb", NULL)) + 32768;
extrambank = extram = (Uint8 *)SDL_realloc(SDL_LoadFile("rom.sav", NULL), 32768);
LCDC = 145;
DIV = 44032;
SDL_Init(SDL_INIT_VIDEO);
SDL_Renderer *renderer = SDL_CreateRenderer(
SDL_CreateWindow("pokegb", 0, 0, 800, 720, SDL_WINDOW_SHOWN), -1,
SDL_RENDERER_PRESENTVSYNC);
SDL_CreateWindow("pokegb", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
800, 720, SDL_WINDOW_SHOWN), -1, SDL_RENDERER_PRESENTVSYNC);
SDL_Texture *texture = SDL_CreateTexture(
renderer, SDL_PIXELFORMAT_RGBA32, SDL_TEXTUREACCESS_STREAMING, 160, 144);
key_state = SDL_GetKeyboardState(0);

ot = SDL_GetTicks64();
while (1) {
prev_cycles = cycles;
if (IME & IF & io[511]) {
Expand Down Expand Up @@ -208,7 +202,7 @@ int main() {
OP5_FLAG(32, 24) // JR i8 / JR <condition>, i8
tmp8 = mem8(PC++);
if (carry)
PC += (int8_t)tmp8, tick();
PC += (Sint8)tmp8, tick();
break;

case 39: // DAA
Expand Down Expand Up @@ -325,7 +319,7 @@ int main() {
OP8_REL(56) // SRL r8 / SRL (HL)
carry = tmp8 & 1;
tmp8 = (opcode & 48) == 32
? (int8_t)tmp8 >> 1
? (Sint8)tmp8 >> 1
: tmp8 / 2 + (opcode & 32 ? 0
: opcode & 16 ? (F * 8 & 128)
: carry * 128);
Expand Down Expand Up @@ -368,8 +362,8 @@ int main() {
break;

case 248: // LD HL, SP + i8
HL = SP + (int8_t)(tmp8 = mem8(PC++));
set_flags(0, 1, 0, SP % 16 + tmp8 % 16 > 15, (uint8_t)SP + tmp8 > 255);
HL = SP + (Sint8)(tmp8 = mem8(PC++));
set_flags(0, 1, 0, SP % 16 + tmp8 % 16 > 15, (Uint8)SP + tmp8 > 255);
tick();
break;

Expand All @@ -383,20 +377,20 @@ int main() {
if (++ppu_dot == 456) {
if (LY < 144)
for (tmp = 160; --tmp >= 0;) {
uint8_t is_window =
Uint8 is_window =
LCDC & 32 && LY >= io[330] && tmp >= io[331] - 7,
x_offset = is_window ? tmp - io[331] + 7 : tmp + io[323],
y_offset = is_window ? LY - io[330] : LY + io[322];
uint16_t
Uint16
palette_index = 0,
tile = video_ram[(LCDC & (is_window ? 64 : 8) ? 7 : 6) << 10 |
y_offset / 8 * 32 + x_offset / 8],
color = get_color(LCDC & 16 ? tile : 256 + (int8_t)tile,
color = get_color(LCDC & 16 ? tile : 256 + (Sint8)tile,
y_offset & 7, 7 - x_offset & 7);

if (LCDC & 2)
for (uint8_t *sprite = io; sprite < io + 160; sprite += 4) {
uint8_t sprite_x = tmp - sprite[1] + 8,
for (Uint8 *sprite = io; sprite < io + 160; sprite += 4) {
Uint8 sprite_x = tmp - sprite[1] + 8,
sprite_y = LY - *sprite + 16,
sprite_color = get_color(
sprite[2], sprite_y ^ (sprite[3] & 64 ? 7 : 0),
Expand All @@ -422,8 +416,19 @@ int main() {
SDL_RenderPresent(renderer);
SDL_Event event;
while (SDL_PollEvent(&event))
if (event.type == SDL_QUIT)
if (event.type == SDL_QUIT) {
SDL_RWops *sav = SDL_RWFromFile("rom.sav", "wb");
SDL_RWwrite(sav, extram, 1, 32768);
SDL_RWclose(sav);
return 0;
}
nt = SDL_GetTicks64();
comp -= delay = comp += 16.7427 - (nt - ot);
ot = nt;
if(delay > 0) {
SDL_Delay(delay);
ot = SDL_GetTicks64();
}
}

LY = (LY + 1) % 154;
Expand Down