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OAM DMA: implemented missing dma transfer from VRAM

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This commit is contained in:
Bruno Duarte Gouveia
2018-11-09 22:40:12 +00:00
parent 91cbfff6a3
commit c742cb8fc8
1 changed files with 15 additions and 6 deletions
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21
gb.v
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@@ -63,6 +63,13 @@ wire sel_zpram = (cpu_addr[15:7] == 9'b111111111) && // 127 bytes zero pageram a
(cpu_addr != 16'hffff);
wire sel_audio = (cpu_addr[15:8] == 8'hff) && // audio reg ff10 - ff3f
((cpu_addr[7:5] == 3'b001) || (cpu_addr[7:4] == 4'b0001));
//DMA can select from $0000 to $F100
wire dma_sel_rom = !dma_addr[15]; // lower 32k are rom
wire dma_sel_cram = dma_addr[15:13] == 3'b101; // 8k cart ram at $a000
wire dma_sel_vram = dma_addr[15:13] == 3'b100; // 8k video ram at $8000
wire dma_sel_iram = (dma_addr[15:14] == 2'b11) && (dma_addr[15:8] != 8'hff); // 8k internal ram at $c000
// the boot roms sees a special $42 flag in $ff50 if it's supposed to to a fast boot
wire sel_fast = fast_boot && cpu_addr == 16'hff50 && boot_rom_enabled;
@@ -251,7 +258,7 @@ wire [7:0] video_do;
wire [12:0] video_addr;
wire [15:0] dma_addr;
wire video_rd, dma_rd;
wire [7:0] dma_data = (dma_addr[15:14]==2'b11)?iram_do:cart_do;
wire [7:0] dma_data = dma_sel_iram?iram_do:dma_sel_vram?vram_do:cart_do;
video video (
.reset ( reset ),
@@ -284,7 +291,7 @@ video video (
wire cpu_wr_vram = sel_vram && !cpu_wr_n;
wire [7:0] vram_do;
wire vram_wren = video_rd?1'b0:cpu_wr_vram;
wire [12:0] vram_addr = video_rd?video_addr:cpu_addr[12:0];
wire [12:0] vram_addr = video_rd?video_addr:(dma_rd&&dma_sel_vram)?dma_addr[12:0]:cpu_addr[12:0];
spram #(13) vram (
.clock ( clk ),
@@ -313,8 +320,8 @@ spram #(7) zpram (
// ------------------------- 8k internal ram --------------------------
// --------------------------------------------------------------------
wire iram_wren = dma_rd?1'b0:cpu_wr_iram;
wire [12:0] iram_addr = dma_rd?dma_addr[12:0]:cpu_addr[12:0];
wire iram_wren = (dma_rd&&dma_sel_iram)?1'b0:cpu_wr_iram;
wire [12:0] iram_addr = (dma_rd&&dma_sel_iram)?dma_addr[12:0]:cpu_addr[12:0];
wire cpu_wr_iram = sel_iram && !cpu_wr_n;
wire [7:0] iram_do;
@@ -342,9 +349,11 @@ end
// combine boot rom data with cartridge data
wire [7:0] rom_do = ((cpu_addr[14:8] == 7'h00) && boot_rom_enabled)?boot_rom_do:cart_do;
wire is_dma_cart_addr = (dma_sel_rom || dma_sel_cram); //rom or external ram
assign cart_di = cpu_do;
assign cart_addr = dma_rd?dma_addr:cpu_addr;
assign cart_rd = dma_rd || ((sel_rom || sel_cram) && !cpu_rd_n);
assign cart_addr = (dma_rd&&is_dma_cart_addr)?dma_addr:cpu_addr;
assign cart_rd = (dma_rd&&is_dma_cart_addr) || ((sel_rom || sel_cram) && !cpu_rd_n);
assign cart_wr = (sel_rom || sel_cram) && !cpu_wr_n;
wire [7:0] boot_rom_do;