forked from KolibriOS/kolibrios
Rustem Gimadutdinov (rgimad)
1c00c160a2
git-svn-id: svn://kolibrios.org@8734 a494cfbc-eb01-0410-851d-a64ba20cac60
780 lines
20 KiB
PHP
780 lines
20 KiB
PHP
; initalize the emulator
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align 4
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proc chip8_init stdcall
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; destroys: nothing, mb flags
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push eax ecx
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mov word [P_C], 0x200
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mov word [opcode], 0
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mov word [I], 0
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mov word [S_P], 0
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;DEBUGF DBG_INFO, "ESP = %x\n", esp
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stdcall _memset, memory, 0, MEM_SIZE
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stdcall _memset, V, 0, 16
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stdcall _memset, gfx, 0, GFX_SIZE
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stdcall _memset, stackmem, 0, 2*STACK_SIZE ; 2 = sizeof(dw)
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stdcall _memset, key, 0, KEY_SIZE
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;DEBUGF DBG_INFO, "ESP = %x\n", esp
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mcall 66, 1, 0 ; set ASCII keyboard mode
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xor ecx, ecx
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@@:
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cmp ecx, 80
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jge @f
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mov al, byte [chip8_fontset + ecx]
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mov byte [memory + FONTSET_ADDRESS + ecx], al
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inc ecx
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jmp @b
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@@:
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mov byte [chip8_draw_flag], 1
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mov byte [delay_timer], 0
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mov byte [sound_timer], 0
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stdcall _getseed
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stdcall _srand, eax
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stdcall _rand
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DEBUGF DBG_INFO, "rand() = %u\n", eax
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;stdcall _rand
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;DEBUGF DBG_INFO, "rand() = %u\n", eax
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;stdcall _rand
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;DEBUGF DBG_INFO, "rand() = %u\n", eax
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;stdcall _rand
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;DEBUGF DBG_INFO, "rand() = %u\n", eax
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;stdcall _rand
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;DEBUGF DBG_INFO, "rand() = %u\n", eax
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;mov word [opcode], 0xBFAF
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;movzx eax, word [opcode]
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;mov eax, 0xABCDEF92
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;stdcall unknown_opcode, eax
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;DEBUGF DBG_INFO, "testprint\n"
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pop ecx eax
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ret
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endp
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; load game from file to memory
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align 4
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proc chip8_loadgame stdcall, struct_ptr: dword
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; in: struct_ptr - pointer to structure for sysfn70
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; out: ZF = 1 file loaded successfully
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; ZF = 0 error
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; destroys: only flags
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push eax ebx
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mov eax, 70
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mov ebx, [struct_ptr]
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int 0x40
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cmp eax, 0
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je @f
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cmp eax, 6
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je @f
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jmp .load_fail
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@@:
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mov eax, 1
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jmp .ret
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.load_fail:
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xor eax, eax
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.ret:
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test eax, eax
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pop ebx eax
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ret
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endp
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; emulate one cycle
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align 4
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proc chip8_emulatecycle stdcall
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; destroys: ?
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locals
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x db ?
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y db ?
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n db ?
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kk db ?
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nnn dw ?
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endl
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; fetch:
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movzx ecx, word [P_C]
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movzx ax, byte [memory + ecx]
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shl ax, 8
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movzx bx, byte [memory + 1 + ecx]
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or ax, bx
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mov word [opcode], ax
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DEBUGF DBG_INFO, "opcode = 0x%x, ax = 0x%x\n", [opcode]:4, ax
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shr ax, 8
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and ax, 0x000F
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mov byte [x], al
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mov ax, word [opcode]
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shr ax, 4
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and ax, 0x000F
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mov byte [y], al
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mov ax, word [opcode]
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and ax, 0x000F
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mov byte [n], al
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mov ax, word [opcode]
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and ax, 0x00FF
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mov byte [kk], al
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mov ax, word [opcode]
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and ax, 0x0FFF
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mov word [nnn], ax
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; DEBUGF DBG_INFO, "P_C: 0x%x Op: 0x%x\n", [P_C], [opcode]:4 ; was word word
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; TODO test this and watch values of x, y, n, kk, nnn
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; decode & execute
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; sw1
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mov ax, word [opcode]
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and ax, 0xF000
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cmp ax, 0x0000
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je .sw1_case_0000
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cmp ax, 0x1000
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je .sw1_case_1000
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cmp ax, 0x2000
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je .sw1_case_2000
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cmp ax, 0x3000
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je .sw1_case_3000
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cmp ax, 0x4000
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je .sw1_case_4000
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cmp ax, 0x5000
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je .sw1_case_5000
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cmp ax, 0x6000
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je .sw1_case_6000
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cmp ax, 0x7000
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je .sw1_case_7000
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cmp ax, 0x8000
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je .sw1_case_8000
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cmp ax, 0x9000
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je .sw1_case_9000
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cmp ax, 0xA000
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je .sw1_case_A000
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cmp ax, 0xB000
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je .sw1_case_B000
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cmp ax, 0xC000
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je .sw1_case_C000
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cmp ax, 0xD000
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je .sw1_case_D000
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cmp ax, 0xE000
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je .sw1_case_E000
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cmp ax, 0xF000
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je .sw1_case_F000
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jmp .sw1_default
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.sw1_case_0000:
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; sw2
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cmp byte [kk], 0xE0
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je .sw2_case_E0
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cmp byte [kk], 0xEE
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je .sw2_case_EE
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jmp .sw2_default
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.sw2_case_E0: ; clear the screen
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stdcall _memset, gfx, 0, GFX_SIZE
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mov byte [chip8_draw_flag], 1
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add word [P_C], 2
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jmp .sw2_end
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.sw2_case_EE: ; TODO check!!; ret
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dec word [S_P]
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movzx ecx, word [S_P]
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mov ax, word [stackmem + ecx*2]
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mov word [P_C], ax
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jmp .sw2_end
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.sw2_default:
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movzx eax, word [opcode]
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stdcall unknown_opcode, eax
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.sw2_end:
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jmp .sw1_end
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.sw1_case_1000: ; TODO check; 1nnn: jump to address nnn
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mov ax, word [nnn]
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mov word [P_C], ax
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jmp .sw1_end
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.sw1_case_2000: ; TODO check; 2nnn: call address nnn
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mov ax, word [P_C]
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add ax, 2
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movzx ecx, word [S_P]
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mov word [stackmem + ecx*2], ax
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inc word [S_P]
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mov ax, word [nnn]
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mov word [P_C], ax
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jmp .sw1_end
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.sw1_case_3000: ; 3xkk: skip next instr if V[x] = kk
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movzx ecx, byte [x]
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mov al, byte [V + ecx]
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mov bl, byte [kk]
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mov cx, 2
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cmp al, bl
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jne @f
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mov cx, 4
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@@:
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add word [P_C], cx
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jmp .sw1_end
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.sw1_case_4000: ; 4xkk: skip next instr if V[x] != kk
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movzx ecx, byte [x]
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mov al, byte [V + ecx]
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mov bl, byte [kk]
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mov cx, 2
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cmp al, bl
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je @f
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mov cx, 4
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@@:
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add word [P_C], cx
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jmp .sw1_end
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.sw1_case_5000: ; 5xy0: skip next instr if V[x] == V[y]
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movzx ecx, byte [x]
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mov al, byte [V + ecx]
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movzx ecx, byte [y]
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mov bl, byte [V + ecx]
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mov cx, 2
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cmp al, bl
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jne @f
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mov cx, 4
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@@:
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add word [P_C], cx
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jmp .sw1_end
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.sw1_case_6000: ; 6xkk: set V[x] = kk
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movzx ecx, byte [x]
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mov bl, byte [kk]
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mov byte [V + ecx], bl
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add word [P_C], 2
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jmp .sw1_end
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.sw1_case_7000: ; 7xkk: set V[x] = V[x] + kk
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movzx ecx, byte [x]
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mov bl, byte [kk]
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add byte [V + ecx], bl
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add word [P_C], 2
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jmp .sw1_end
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.sw1_case_8000: ; 8xyn: Arithmetic stuff
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; sw3
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cmp byte [n], 0x0
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je .sw3_case_0
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cmp byte [n], 0x1
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je .sw3_case_1
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cmp byte [n], 0x2
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je .sw3_case_2
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cmp byte [n], 0x3
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je .sw3_case_3
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cmp byte [n], 0x4
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je .sw3_case_4
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cmp byte [n], 0x5
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je .sw3_case_5
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cmp byte [n], 0x6
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je .sw3_case_6
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cmp byte [n], 0x7
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je .sw3_case_7
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cmp byte [n], 0xE
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je .sw3_case_E
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jmp .sw3_default
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.sw3_case_0: ; V[x] = V[y]
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movzx ecx, byte [x]
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movzx edx, byte [y]
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mov al, byte [V + edx]
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mov byte [V + ecx], al
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jmp .sw3_end
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.sw3_case_1: ; V[x] = V[x] | V[y]
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movzx ecx, byte [x]
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movzx edx, byte [y]
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mov al, byte [V + ecx]
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or al, byte [V + edx]
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mov byte [V + ecx], al
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jmp .sw3_end
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.sw3_case_2: ; V[x] = V[x] & V[y]
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movzx ecx, byte [x]
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movzx edx, byte [y]
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mov al, byte [V + ecx]
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and al, byte [V + edx]
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mov byte [V + ecx], al
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jmp .sw3_end
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.sw3_case_3: ; V[x] = V[x] ^ V[y]
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movzx ecx, byte [x]
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movzx edx, byte [y]
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mov al, byte [V + ecx]
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xor al, byte [V + edx]
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mov byte [V + ecx], al
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jmp .sw3_end
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.sw3_case_4: ; V[x] = V[x] + V[y]; if carry, move 1 to V[0xF]
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movzx ecx, byte [x]
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movzx edx, byte [y]
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movzx ax, byte [V + ecx]
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movzx bx, byte [V + edx]
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add ax, bx
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mov byte [V + ecx], al
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xor cl, cl
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cmp ax, 255
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jbe @f
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inc cl
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@@:
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mov byte [V + 0xF], cl
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jmp .sw3_end
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.sw3_case_5: ;TODO check; V[x] = V[x] - V[y]; if no borrow, move 1 to V[0xF]
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movzx ecx, byte [x]
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movzx edx, byte [y]
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mov al, byte [V + ecx]
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mov bl, byte [V + edx]
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sub al, bl
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mov byte [V + ecx], al
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xor cl, cl
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cmp al, bl
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jbe @f
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inc cl
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@@:
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mov byte [V + 0xF], cl
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jmp .sw3_end
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.sw3_case_6: ; TODO check; V[x] = V[x] SHR 1 ; V[0xF] = least-significant bit of V[x] before shift
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movzx ecx, byte [x]
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mov al, byte [V + ecx]
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and al, 0x01
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mov byte [V + 0xF], al
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shr byte [V + ecx], 1
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jmp .sw3_end
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.sw3_case_7: ; TODO check; V[x] = V[y] - V[x]; if no borrow, move 1 to V[0xF]
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movzx ecx, byte [y]
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movzx edx, byte [x]
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mov al, byte [V + ecx]
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mov bl, byte [V + edx]
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sub al, bl
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mov byte [V + ecx], al
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xor cl, cl
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cmp al, bl
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jbe @f
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inc cl
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@@:
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mov byte [V + 0xF], cl
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jmp .sw3_end
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.sw3_case_E: ; TODO check; V[0xF] = most-significant bit of V[x] before shift
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movzx ecx, byte [x]
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mov al, byte [V + ecx]
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shr al, 7
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and al, 0x01
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mov byte [V + 0xF], al
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shl byte [V + ecx], 1
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jmp .sw3_end
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.sw3_default:
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movzx eax, word [opcode]
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stdcall unknown_opcode, eax
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.sw3_end:
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add word [P_C], 2
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jmp .sw1_end
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.sw1_case_9000: ; TODO check; 9xy0: skip instruction if V[x] != V[y]
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movzx ecx, byte [x]
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mov al, byte [V + ecx]
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movzx ecx, byte [y]
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mov bl, byte [V + ecx]
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mov cx, 2
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cmp al, bl
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je @f
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mov cx, 4
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@@:
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add word [P_C], cx
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jmp .sw1_end
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.sw1_case_A000: ; Annn: set I to address nnn
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mov ax, word [nnn]
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mov word [I], ax
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add word [P_C], 2
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jmp .sw1_end
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.sw1_case_B000: ; Bnnn: jump to location nnn + V[0]
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mov ax, word [nnn]
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movzx bx, byte [V]
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add ax, bx
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mov word [P_C], ax
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jmp .sw1_end
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.sw1_case_C000: ; TODO check; Cxkk: V[x] = random byte AND kk
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stdcall _rand
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and al, byte [kk]
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movzx ecx, byte [x]
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mov byte [V + ecx], al
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add word [P_C], 2
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jmp .sw1_end
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.sw1_case_D000: ; TODO check; Dxyn: Display an n-byte sprite starting at memory location I at (Vx, Vy) on the screen, VF = collision
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movzx ecx, byte [x]
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movzx eax, byte [V + ecx]
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movzx ecx, byte [y]
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movzx ebx, byte [V + ecx]
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movzx ecx, byte [n]
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stdcall chip8_draw_sprite, eax, ebx, ecx
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mov byte [chip8_draw_flag], 1
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add word [P_C], 2
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jmp .sw1_end
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.sw1_case_E000: ; TODO check; key-pressed events
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cmp byte [kk], 0x9E
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je .sw5_case_9E
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cmp byte [kk], 0xA1
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je .sw5_case_A1
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jmp .sw5_default
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.sw5_case_9E: ; skip next instruction if key V[X] is pressed
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movzx ecx, byte [x]
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movzx edx, byte [V + ecx]
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mov bl, byte [key + edx]
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mov ax, 2
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cmp bl, 1
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jne .sw5_case_9E_endcheck
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mov ax, 4
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mov byte [key + edx], 0 ; release pressed key
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.sw5_case_9E_endcheck:
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add word [P_C], ax
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jmp .sw5_end
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.sw5_case_A1: ; skip next instruction if key V[X] is NOT pressed
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movzx ecx, byte [x]
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movzx edx, byte [V + ecx]
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mov bl, byte [key + edx]
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mov ax, 4
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cmp bl, 1
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jne .sw5_case_A1_endcheck
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mov ax, 2
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.sw5_case_A1_endcheck:
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mov byte [key + edx], 0 ; release pressed key
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add word [P_C], ax
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jmp .sw5_end
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.sw5_default:
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movzx eax, word [opcode]
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stdcall unknown_opcode, eax
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.sw5_end:
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jmp .sw1_end
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.sw1_case_F000: ; misc
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cmp byte [kk], 0x07
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je .sw4_case_07
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cmp byte [kk], 0x0A
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je .sw4_case_0A
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cmp byte [kk], 0x15
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je .sw4_case_15
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cmp byte [kk], 0x18
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je .sw4_case_18
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cmp byte [kk], 0x1E
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je .sw4_case_1E
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cmp byte [kk], 0x29
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je .sw4_case_29
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cmp byte [kk], 0x33
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je .sw4_case_33
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cmp byte [kk], 0x55
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je .sw4_case_55
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cmp byte [kk], 0x65
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je .sw4_case_65
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jmp .sw4_default
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.sw4_case_07: ; TODO check; V[X] = delay timer
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mov al, byte [delay_timer]
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movzx ecx, byte [x]
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mov byte [V + ecx], al
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add word [P_C], 2
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jmp .sw4_end
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.sw4_case_0A: ; TODO check; wait for key instruction
|
|
;.sw4_case_0A_loop:
|
|
;mcall 2
|
|
;stdcall keyboard_update, eax
|
|
xor ecx, ecx
|
|
.sw4_case_0A_loop2:
|
|
cmp ecx, KEY_SIZE
|
|
jae .sw4_case_0A_loop_end ;
|
|
|
|
cmp byte [key + ecx], 1
|
|
jne .sw4_case_0A_loop2_endcheck
|
|
|
|
movzx edx, byte [x]
|
|
mov byte [V + edx], cl
|
|
mov byte [key + ecx], 0 ; release pressed key
|
|
;jmp .sw4_case_0A_loop_end
|
|
add word [P_C], 2
|
|
jmp .sw4_end
|
|
|
|
.sw4_case_0A_loop2_endcheck:
|
|
inc ecx
|
|
jmp .sw4_case_0A_loop2
|
|
|
|
;jmp .sw4_case_0A_loop
|
|
.sw4_case_0A_loop_end:
|
|
;add word [P_C], 2
|
|
jmp .sw4_end
|
|
|
|
.sw4_case_15: ; TODO check; delay_timer = V[X]
|
|
movzx ecx, byte [x]
|
|
mov al, byte [V + ecx]
|
|
mov byte [delay_timer], al
|
|
add word [P_C], 2
|
|
jmp .sw4_end
|
|
|
|
.sw4_case_18: ; TODO check; sound_timer = V[X]
|
|
movzx ecx, byte [x]
|
|
mov al, byte [V + ecx]
|
|
mov byte [sound_timer], al
|
|
add word [P_C], 2
|
|
jmp .sw4_end
|
|
|
|
.sw4_case_1E: ; I = I + V[X]
|
|
; V[0xF] = (I + V[x] > 0xfff) ? 1 : 0; (TODO?? (no this line in other chip8 emulators))
|
|
movzx ecx, byte [x]
|
|
movzx ax, byte [V + ecx]
|
|
add word [I], ax
|
|
add word [P_C], 2
|
|
jmp .sw4_end
|
|
|
|
.sw4_case_29: ; TODO check; I = location of font for character V[X]
|
|
movzx ecx, byte [x]
|
|
movzx ax, byte [V + ecx]
|
|
mov bx, FONTSET_BYTES_PER_CHAR
|
|
mul bx
|
|
mov word [I], ax
|
|
add word [P_C], 2
|
|
jmp .sw4_end
|
|
|
|
.sw4_case_33: ; TODO check; Store BCD for V[X] starting at address I
|
|
movzx ecx, byte [x]
|
|
movzx ebx, byte [V + ecx]
|
|
|
|
stdcall mod_div, ebx, 1000, 100
|
|
movzx ecx, word [I]
|
|
mov byte [memory + ecx], al
|
|
|
|
stdcall mod_div, ebx, 100, 10
|
|
mov byte [memory + ecx + 1], al
|
|
|
|
stdcall mod_div, ebx, 10, 1
|
|
mov byte [memory + ecx + 2], al
|
|
|
|
add word [P_C], 2
|
|
jmp .sw4_end
|
|
|
|
.sw4_case_55: ; TODO check; Copy sprite from registers 0 to X into memory at address I
|
|
movzx edx, word [I]
|
|
xor ecx, ecx
|
|
.for_sw4_1:
|
|
movzx eax, byte [x]
|
|
cmp ecx, eax
|
|
ja .for_sw4_1_end
|
|
|
|
mov al, byte [V + ecx]
|
|
mov byte [memory + ecx + edx], al
|
|
|
|
inc ecx
|
|
jmp .for_sw4_1
|
|
.for_sw4_1_end:
|
|
movzx ax, byte [x]
|
|
inc ax
|
|
add word [I], ax
|
|
|
|
add word [P_C], 2
|
|
jmp .sw4_end
|
|
|
|
.sw4_case_65: ; TODO check; Copy sprite from memory at address X into registers 0 to I
|
|
movzx edx, word [I]
|
|
xor ecx, ecx
|
|
.for_sw4_2:
|
|
movzx eax, byte [x]
|
|
cmp ecx, eax
|
|
ja .for_sw4_2_end
|
|
|
|
mov al, byte [memory + ecx + edx]
|
|
mov byte [V + ecx], al
|
|
|
|
inc ecx
|
|
jmp .for_sw4_2
|
|
.for_sw4_2_end:
|
|
movzx ax, byte [x]
|
|
inc ax
|
|
add word [I], ax
|
|
|
|
add word [P_C], 2
|
|
jmp .sw4_end
|
|
|
|
.sw4_default:
|
|
movzx eax, word [opcode]
|
|
stdcall unknown_opcode, eax
|
|
.sw4_end:
|
|
jmp .sw1_end
|
|
|
|
.sw1_default:
|
|
movzx eax, word [opcode]
|
|
stdcall unknown_opcode, eax
|
|
|
|
.sw1_end:
|
|
ret
|
|
endp
|
|
|
|
|
|
; tick the timers
|
|
align 4
|
|
proc chip8_tick stdcall
|
|
; destroys: flags
|
|
cmp byte [delay_timer], 0
|
|
jz @f
|
|
dec byte [delay_timer]
|
|
@@:
|
|
cmp byte [sound_timer], 0
|
|
jz .ret
|
|
dec byte [sound_timer]
|
|
cmp byte [sound_timer], 0
|
|
jnz @f
|
|
DEBUGF DBG_INFO, "BEEP!\n"
|
|
@@:
|
|
.ret:
|
|
ret
|
|
endp
|
|
|
|
|
|
; print unknown opcode error & exit
|
|
align 4
|
|
proc unknown_opcode stdcall, op:word
|
|
DEBUGF DBG_ERR, "Error: unknown opcode 0x%x\n", [op]:4
|
|
mov eax, -1
|
|
int 0x40
|
|
ret
|
|
endp
|
|
|
|
; draw sprite from memory to gfx; TODO check;
|
|
; if collision then V[0xF] = 1
|
|
align 4
|
|
proc chip8_draw_sprite stdcall, col: dword, row: dword, n: dword
|
|
locals
|
|
byte_index dd ?
|
|
bit_index dd ?
|
|
pixelp dd ?
|
|
temp dd ?
|
|
_byte db ?
|
|
_bit db ?
|
|
endl
|
|
|
|
DEBUGF DBG_INFO, "draw_sprite x = %u, y = %u, n = %u\n", [col], [row], [n]
|
|
|
|
movzx eax, word [I]
|
|
mov ebx, dword [memory + eax]
|
|
mov ecx, dword [memory + eax + 4]
|
|
DEBUGF DBG_INFO, "I = %x, at I: %x, at I + 4: %x\n", eax, ebx, ecx
|
|
|
|
mov byte [V + 0xF], 0
|
|
mov dword [byte_index], 0
|
|
.for1:
|
|
movzx eax, byte [n]
|
|
cmp dword [byte_index], eax
|
|
jae .for1_end
|
|
|
|
movzx ecx, word [I]
|
|
add ecx, dword [byte_index]
|
|
mov al, byte [memory + ecx]
|
|
mov byte [_byte], al
|
|
mov dword [bit_index], 0
|
|
.for2:
|
|
cmp dword [bit_index], 8
|
|
jae .for2_end
|
|
|
|
mov ecx, dword [bit_index]
|
|
mov al, byte [_byte]
|
|
shr al, cl
|
|
and al, 1
|
|
mov byte [_bit], al
|
|
|
|
mov eax, dword [row]
|
|
add eax, dword [byte_index]
|
|
imul eax, GFX_COLS
|
|
add eax, dword [col]
|
|
add eax, 7
|
|
sub eax, dword [bit_index]
|
|
add eax, gfx
|
|
mov dword [pixelp], eax
|
|
|
|
; DEBUGF DBG_INFO, "gfx = %x, pixelp = %x\n", gfx, edx
|
|
|
|
cmp byte [_bit], 1
|
|
jne .if2_end
|
|
|
|
mov eax, dword [pixelp]
|
|
cmp byte [eax], 1
|
|
jne .if2_end
|
|
|
|
mov byte [V + 0xF], 1
|
|
.if2_end:
|
|
|
|
mov ebx, dword [pixelp]
|
|
mov al, byte [ebx]
|
|
xor al, byte [_bit]
|
|
mov byte [ebx], al
|
|
|
|
inc dword [bit_index]
|
|
jmp .for2
|
|
.for2_end:
|
|
|
|
inc dword [byte_index]
|
|
jmp .for1
|
|
.for1_end:
|
|
|
|
ret
|
|
endp
|