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- `timescale 1 ns / 1 ns
- //////////////////////////////////////////////////////////////////////////////////
- // Company: Rehkopf
- // Engineer: Rehkopf
- //
- // Create Date: 01:13:46 05/09/2009
- // Design Name:
- // Module Name: address
- // Project Name:
- // Target Devices:
- // Tool versions:
- // Description: Address logic w/ SaveRAM masking
- //
- // Dependencies:
- //
- // Revision:
- // Additional Comments:
- //
- //////////////////////////////////////////////////////////////////////////////////
- module address(
- input CLK,
- input [2:0] MAPPER, // MCU detected mapper
- input [23:0] SNES_ADDR, // requested address from SNES
- input SNES_CS, // "CART" pin from SNES (active low)
- output [22:0] ROM_ADDR, // Address to request from SRAM0
- output ROM_SEL, // enable SRAM0 (active low)
- input MCU_OVR, // enable MCU master mode (active low)
- input MODE, // MCU(1) or SNES(0) ("bus phase")
- output IS_SAVERAM, // address/CS mapped as SRAM?
- output IS_ROM, // address mapped as ROM?
- output IS_WRITABLE, // address somehow mapped as writable area?
- input [23:0] MCU_ADDR, // allow address to be set externally
- input ADDR_WRITE,
- output ROM_ADDR0,
- input [23:0] SAVERAM_MASK,
- input [23:0] ROM_MASK,
- input use_msu,
- output msu_enable,
- output use_bsx,
- input [14:0] bsx_regs
- );
- wire [1:0] SRAM_BANK;
- wire [23:0] SRAM_ADDR_FULL;
- /* currently supported mappers:
- Index Mapper
- 000 HiROM
- 001 LoROM
- 010 ExHiROM (48-64Mbit)
- 011 BS-X
- 110 brainfuck interleaved 96MBit Star Ocean =)
- 111 menu (ROM in upper SRAM)
- */
- /* HiROM: SRAM @ Bank 0x30-0x3f, 0xb0-0xbf
- Offset 6000-7fff */
- assign IS_ROM = ( (MAPPER == 3'b000) ? ((!SNES_ADDR[22] & SNES_ADDR[15])
- |(SNES_ADDR[22]))
- : (MAPPER == 3'b001) ? ((!SNES_ADDR[22] & SNES_ADDR[15])
- |(SNES_ADDR[22]))
- : (MAPPER == 3'b010) ? ((!SNES_ADDR[22] & SNES_ADDR[15])
- |(SNES_ADDR[22]))
- : (MAPPER == 3'b011) ? ((!SNES_ADDR[22] & SNES_ADDR[15])
- |(SNES_ADDR[22]))
- : (MAPPER == 3'b110) ? ((!SNES_ADDR[22] & SNES_ADDR[15])
- |(SNES_ADDR[22]))
- : (MAPPER == 3'b111) ? ((!SNES_ADDR[22] & SNES_ADDR[15])
- |(SNES_ADDR[22]))
- : 1'b0);
- assign IS_SAVERAM = ((MAPPER == 3'b000 || MAPPER == 3'b010 || MAPPER == 3'b110 || MAPPER == 3'b111) ? (!SNES_ADDR[22]
- & SNES_ADDR[21:20]
- & &SNES_ADDR[14:13]
- & !SNES_ADDR[15]
- & SNES_CS
- )
- /* LoROM: SRAM @ Bank 0x70-0x7d, 0xf0-0xfd
- Offset 0000-7fff TODO: 0000-ffff for
- small ROMs */
- :(MAPPER == 3'b001) ? (&SNES_ADDR[22:20]
- & (SNES_ADDR[19:16] < 4'b1110)
- & !SNES_ADDR[15]
- & !SNES_CS)
- /* BS-X: SRAM @ Bank 0x10-0x17
- Offset 5000-5fff */
- :(MAPPER == 3'b011) ? ((SNES_ADDR[23:19] == 5'b00010)
- & (SNES_ADDR[15:12] == 4'b0101)
- )
- : 1'b0);
- assign IS_WRITABLE = IS_SAVERAM | (
- (MAPPER == 3'b011)
- ? (
- (bsx_regs[3] && SNES_ADDR[23:20]==4'b0110)
- |(!bsx_regs[5] && SNES_ADDR[23:20]==4'b0100)
- |(!bsx_regs[6] && SNES_ADDR[23:20]==4'b0101)
- |(SNES_ADDR[23:19] == 5'b01110)
- |(SNES_ADDR[23:21] == 3'b001 && SNES_ADDR[15:13] == 3'b011))
- : 1'b0);
- /* BSX regs:
- Index Function
- 1 0=map flash to ROM area; 1=map PRAM to ROM area
- 2 1=HiROM; 0=LoROM
- 3 1=Mirror PRAM @60-6f:0000-ffff
- 5 1=DO NOT mirror PRAM @40-4f:0000-ffff
- 6 1=DO NOT mirror PRAM @50-5f:0000-ffff
- 7 1=map BSX cartridge ROM @00-1f:8000-ffff
- 8 1=map BSX cartridge ROM @80-9f:8000-ffff
- */
- assign SRAM_ADDR_FULL = (MODE) ? MCU_ADDR
- : ((MAPPER == 3'b000) ?
- (IS_SAVERAM ? 24'hE00000 + ((SNES_ADDR[14:0] - 15'h6000) & SAVERAM_MASK)
- : ({1'b0, SNES_ADDR[22:0]} & ROM_MASK))
- :(MAPPER == 3'b001) ?
- (IS_SAVERAM ? 24'hE00000 + (SNES_ADDR[14:0] & SAVERAM_MASK)
- : ({2'b00, SNES_ADDR[22:16], SNES_ADDR[14:0]} & ROM_MASK))
- :(MAPPER == 3'b010) ?
- (IS_SAVERAM ? 24'hE00000 + ((SNES_ADDR[14:0] - 15'h6000) & SAVERAM_MASK)
- : ({1'b0, !SNES_ADDR[23], SNES_ADDR[21:0]} & ROM_MASK))
- :(MAPPER == 3'b011) ?
- (IS_SAVERAM ? 24'hE00000 + {SNES_ADDR[18:16], SNES_ADDR[11:0]}
- : IS_WRITABLE ? (24'h400000 + (SNES_ADDR & 24'h07FFFF))
- : ((bsx_regs[7] && SNES_ADDR[23:21] == 3'b000)
- |(bsx_regs[8] && SNES_ADDR[23:21] == 3'b100))
- ? (24'h800000 + ({1'b0, SNES_ADDR[23:16], SNES_ADDR[14:0]} & 24'h0FFFFF))
- : ((bsx_regs[1] ? 24'h400000 : 24'h000000)
- + bsx_regs[2] ? ({2'b00, SNES_ADDR[21:0]} & (ROM_MASK >> bsx_regs[1]))
- : ({1'b0, SNES_ADDR[23:16], SNES_ADDR[14:0]} & (ROM_MASK >> bsx_regs[1]))))
- :(MAPPER == 3'b110) ?
- (IS_SAVERAM ? 24'hE00000 + ((SNES_ADDR[14:0] - 15'h6000) & SAVERAM_MASK)
- : (SNES_ADDR[15] ? ({1'b0, SNES_ADDR[23:16], SNES_ADDR[14:0]})
- : ({2'b10, SNES_ADDR[23], SNES_ADDR[21:16], SNES_ADDR[14:0]})))
- :(MAPPER == 3'b111) ?
- (IS_SAVERAM ? 24'hFF0000 + ((SNES_ADDR[14:0] - 15'h6000) & SAVERAM_MASK)
- : (({1'b0, SNES_ADDR[22:0]} & ROM_MASK) + 24'hE00000))
- : 24'b0);
- assign ROM_ADDR = SRAM_ADDR_FULL[23:1];
- assign ROM_SEL = 1'b0; // (MODE) ? CS_ARRAY[SRAM_BANK] : IS_SAVERAM ? 4'b1000 : CS_ARRAY[SRAM_BANK];
- assign ROM_ADDR0 = SRAM_ADDR_FULL[0];
- //488888
- assign msu_enable = (!SNES_ADDR[22] && ((SNES_ADDR[15:0] & 16'hfff8) == 16'h2000));
- assign use_bsx = (MAPPER == 3'b011);
- endmodule
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