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Sega Saturn SCU DSP disassembler
4
Written by Angelo Salese
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static const SCUDSP_OPCODE alu_table[16] =
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{ "NOP", 0, 0, 0, }, /* 0000 */
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{ "AND", 0, 0, 0, }, /* 0001 */
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{ "OR ", 0, 0, 0, }, /* 0010 */
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{ "XOR", 0, 0, 0, }, /* 0011 */
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{ "ADD", 0, 0, 0, }, /* 0100 */
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{ "SUB", 0, 0, 0, }, /* 0101 */
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{ "AD2", 0, 0, 0, }, /* 0110 */
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{ "???", 0, 0, 0, }, /* 0111 */
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{ "SR ", 0, 0, 0, }, /* 1000 */
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{ "RR ", 0, 0, 0, }, /* 1001 */
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{ "SL ", 0, 0, 0, }, /* 1010 */
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{ "RL ", 0, 0, 0, }, /* 1011 */
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{ "???", 0, 0, 0, }, /* 1100 */
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{ "???", 0, 0, 0, }, /* 1101 */
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{ "???", 0, 0, 0, }, /* 1110 */
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{ "RL8", 0, 0, 0, }, /* 1111 */
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static const SCUDSP_OPCODE xbus_table[] =
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{ "NOP", 0, 0, 0, }, /* 000 */
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{ "???", 0, 0, 0, }, /* 001 */
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{ "MOV", EA_MUL, EA_P, 0, }, /* 010 */
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{ "MOV", EA_SRCMEMX, EA_P, 0, }, /* 011 */ //MOV %s,P
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{ "MOV", EA_SRCMEMX, EA_X, 0, }, /* 100 */ //MOV %s,X
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{ "???", 0, 0, 0, }, /* 101 */
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{ "???", 0, 0, 0, }, /* 110 */
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{ "???", 0, 0, 0, }, /* 111 */
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static const SCUDSP_OPCODE ybus_table[] =
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{ "NOP", 0, 0, 0, }, /* 000 */
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{ "CLR", 0, EA_A, 0, }, /* 001 */
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{ "MOV", EA_ALU, EA_A, 0, }, /* 010 */
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{ "MOV", EA_SRCMEMY, EA_A, 0, }, /* 011 */ //MOV %s,A
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{ "MOV", EA_SRCMEMY, EA_Y, 0, }, /* 100 */ //MOV %s,Y
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{ "???", 0, 0, 0, }, /* 101 */
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{ "???", 0, 0, 0, }, /* 110 */
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{ "???", 0, 0, 0, }, /* 111 */
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static const SCUDSP_OPCODE d1bus_table[] =
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{ "NOP", 0, 0, 0, }, /* 00 */
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{ "MOV", EA_IMM8, EA_DSTMEM, 0, }, /* 01 */ //MOV %I8,%d
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{ "???", 0, 0, 0, }, /* 10 */
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{ "MOV", EA_SRCMEMD1,0, 0, }, /* 11 */ //MOV %S,%d
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static const SCUDSP_OPCODE mvi_table[] =
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{ "MVI", EA_IMM25, EA_MVIDSTMEM, 0, }, /* 0 */ //"MVI %I,%d"
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{ "MVI", EA_IMM18, EA_MVIDSTMEM, EA_FLAGS, }, /* 1 */ //"MVI %I,%d,%f"
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static const SCUDSP_OPCODE dma_table[] =
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{ "DMA", EA_D0, EA_DMADSTMEM, EA_IMM8, }, /* 000 */ // "DMA%H%A D0,%M,%I",
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{ "DMA", EA_DMASRCMEM, EA_D0, EA_IMM8, }, /* 001 */ // "DMA%H%A %s,D0,%I",
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{ "DMA", 0, 0, 0, }, /* 010 */ // "DMA%H%A D0,%M,%s",
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{ "DMA", 0, 0, 0, }, /* 011 */ // "DMA%H%A %s,D0,%s",
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{ "DMAH", EA_D0, EA_DMADSTMEM, EA_IMM8, }, /* 100 */ // "DMA%H%A D0,%M,%I",
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{ "DMAH", EA_DMASRCMEM, EA_D0, EA_IMM8, }, /* 101 */ // "DMA%H%A %s,D0,%I",
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{ "DMAH", 0, 0, 0, }, /* 110 */ // "DMA%H%A D0,%M,%s",
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{ "DMAH", 0, 0, 0, }, /* 111 */ // "DMA%H%A %s,D0,%s",
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static const SCUDSP_OPCODE jmp_table[] =
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{ "JMP", EA_IMM8, 0, 0, }, /* 0 */ // unconditional
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{ "JMP", EA_IMM8, 0, EA_FLAGS, }, /* 1 */ // conditional
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static const SCUDSP_OPCODE loop_table[] =
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{ "BTM", 0, 0, 0, }, /* 00 */
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{ "LPS", 0, 0, 0, }, /* 01 */
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static const SCUDSP_OPCODE end_table[] =
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{ "END", 0, 0, 0, }, /* 00 */
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{ "ENDI",0, 0, 0, }, /* 01 */
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static const char *const src_mem[] =
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static const char *const dst_mem[] =
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static const char *const mvi_dst_mem[] =
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"PC", /* 1100 */ //???
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static const char *const cond_flags[] =
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/*****************************************************************************/
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static const UINT32 *rombase;
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static void ATTR_PRINTF(1,2) print(const char *fmt, ...)
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output += vsprintf(output, fmt, vl);
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static UINT32 fetch(void)
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static UINT8 add_table(UINT32 cur_opcode)
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UINT8 res = (cur_opcode & 0x00038000) >> 15;
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static UINT32 decode_opcode(UINT32 pc, const SCUDSP_OPCODE *op_table,UINT32 cur_opcode)
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//if (!strcmp(op_table->mnemonic, "jsr") || !strcmp(op_table->mnemonic, "bsr"))
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// flags = DASMFLAG_STEP_OVER;
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//else if (!strcmp(op_table->mnemonic, "rts") || !strcmp(op_table->mnemonic, "rti"))
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// flags = DASMFLAG_STEP_OUT;
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print("%s ", op_table->mnemonic);
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switch(op_table->address_mode_1)
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case EA_ALU: print("ALU "); break;
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case EA_IMM8: print("%02X ",cur_opcode & 0xff); break;
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case EA_IMM18: print("%08X ",cur_opcode & 0x7ffff); break;
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case EA_IMM25: print("%08X ",cur_opcode & 0x1ffffff); break;
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case EA_MUL: print("MUL "); break;
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case EA_SRCMEMX: print("%s ", src_mem[(cur_opcode & 0x00700000) >> 20]); break;
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case EA_SRCMEMY: print("%s ", src_mem[(cur_opcode & 0x0001c000) >> 14]); break;
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case EA_SRCMEMD1: print("%s ", src_mem[(cur_opcode & 0x0000000f) >> 0]); break;
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case EA_D0: print("%d D0 ",add_table(cur_opcode)); break;
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case EA_DMASRCMEM: print("%d %s ",add_table(cur_opcode),src_mem[(cur_opcode & 0x00000300) >> 8]); break;
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switch(op_table->address_mode_2)
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case EA_A: print("A"); break;
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case EA_P: print("P"); break;
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case EA_X: print("X"); break;
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case EA_Y: print("Y"); break;
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case EA_DSTMEM: print("%s ", dst_mem[(cur_opcode & 0x00000f00) >> 8]); break;
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case EA_DMADSTMEM: print("%s ", dst_mem[(cur_opcode & 0x00000300) >> 8]); break;
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case EA_MVIDSTMEM: print("%s ", mvi_dst_mem[(cur_opcode & 0x3c000000) >> 26]); break;
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case EA_D0: print("D0 "); break;
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switch(op_table->address_mode_3)
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case EA_IMM8: print("%02X ",cur_opcode & 0xff); break;
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if(!((cur_opcode >> 19) & 0x20))
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print("%s ", cond_flags[(cur_opcode & 0x0780000) >> 19]);
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CPU_DISASSEMBLE( scudsp )
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switch((opcode & 0xc0000000) >> 30)
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flags = decode_opcode(pc, &alu_table [(opcode & 0x3c000000) >> 26],opcode);
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flags |= decode_opcode(pc, &xbus_table [(opcode & 0x03800000) >> 23],opcode);
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flags |= decode_opcode(pc, &ybus_table [(opcode & 0x000e0000) >> 17],opcode);
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flags |= decode_opcode(pc, &d1bus_table[(opcode & 0x00003000) >> 12],opcode);
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case 2: // move immediate
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flags = decode_opcode(pc, &mvi_table [(opcode & 0x02000000) >> 25],opcode);
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switch((opcode & 0x30000000) >> 28)
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flags = decode_opcode(pc, &dma_table [(opcode & 0x7000) >> 12],opcode);
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flags = decode_opcode(pc, &jmp_table [(opcode & 0x2000000) >> 25],opcode);
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flags = decode_opcode(pc, &loop_table [(opcode & 0x8000000) >> 27],opcode);
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flags = decode_opcode(pc, &end_table [(opcode & 0x8000000) >> 27],opcode);
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return (rombase-oprom) | flags | DASMFLAG_SUPPORTED;
added
removed
src/emu/cpu/scudsp/scudspdasm.c
