Add bit instruction
authorJoshua Wise <joshua@nyus.joshuawise.com>
Sat, 19 Apr 2008 09:45:12 +0000 (05:45 -0400)
committerJoshua Wise <joshua@nyus.joshuawise.com>
Sat, 19 Apr 2008 09:45:12 +0000 (05:45 -0400)
GBZ80Core.v
allinsns.v
insn_bit.v [new file with mode: 0644]

index 3931bdd..45870d1 100644 (file)
 `define STATE_EXECUTE          2'h2
 `define STATE_WRITEBACK                2'h3
 
-`define INSN_LD_reg_imm8       8'b00xxx110
-`define INSN_HALT              8'b01110110
-`define INSN_LD_HL_reg         8'b01110xxx
-`define INSN_LD_reg_HL         8'b01xxx110
-`define INSN_LD_reg_reg                8'b01xxxxxx
-`define INSN_LD_reg_imm16      8'b00xx0001
-`define INSN_LD_SP_HL          8'b11111001
-`define INSN_PUSH_reg          8'b11xx0101
-`define INSN_POP_reg           8'b11xx0001
-`define INSN_LDH_AC            8'b111x0010     // Either LDH A,(C) or LDH (C),A
-`define INSN_LDx_AHL           8'b001xx010     // LDD/LDI A,(HL) / (HL),A
-`define INSN_ALU8              8'b10xxxxxx     // 10 xxx yyy
-`define INSN_ALU8IMM           8'b11xxx110
-`define INSN_NOP               8'b00000000
-`define INSN_RST               8'b11xxx111
-`define INSN_RET               8'b110x1001     // 1 = RETI, 0 = RET
-`define INSN_RETCC             8'b110xx000
-`define INSN_CALL              8'b11001101
-`define INSN_CALLCC            8'b110xx100     // Not that call/cc.
-`define INSN_JP_imm            8'b11000011
-`define INSN_JPCC_imm          8'b110xx010
-`define INSN_ALU_A             8'b00xxx111
-`define INSN_JP_HL             8'b11101001
-`define INSN_JR_imm            8'b00011000
-`define INSN_JRCC_imm          8'b001xx000
-`define INSN_INCDEC16          8'b00xxx011
-`define INSN_VOP_INTR          8'b11111100     // 0xFC is grabbed by the fetch if there is an interrupt pending.
-`define INSN_DI                        8'b11110011
-`define INSN_EI                        8'b11111011
-`define INSN_INCDEC_HL         8'b0011010x
-`define INSN_INCDEC_reg8       8'b00xxx10x
-`define INSN_LD8M_A            8'b111x0000     // 1111 for ld A, x; 1110 for ld x, A; bit 1 specifies 16m8 or 8m8
-`define INSN_LD16M_A           8'b111x1010     // 1111 for ld A, x; 1110 for ld x, A; bit 1 specifies 16m8 or 8m8
-`define INSN_LDBCDE_A          8'b000xx010     // 0000 for BC, 0001 for DE, 1010 for A,(x), 0010 for (x),A
+`define INSN_LD_reg_imm8       9'b000xxx110
+`define INSN_HALT              9'b001110110
+`define INSN_LD_HL_reg         9'b001110xxx
+`define INSN_LD_reg_HL         9'b001xxx110
+`define INSN_LD_reg_reg                9'b001xxxxxx
+`define INSN_LD_reg_imm16      9'b000xx0001
+`define INSN_LD_SP_HL          9'b011111001
+`define INSN_PUSH_reg          9'b011xx0101
+`define INSN_POP_reg           9'b011xx0001
+`define INSN_LDH_AC            9'b0111x0010    // Either LDH A,(C) or LDH (C),A
+`define INSN_LDx_AHL           9'b0001xx010    // LDD/LDI A,(HL) / (HL),A
+`define INSN_ALU8              9'b010xxxxxx    // 10 xxx yyy
+`define INSN_ALU8IMM           9'b011xxx110
+`define INSN_NOP               9'b000000000
+`define INSN_RST               9'b011xxx111
+`define INSN_RET               9'b0110x1001    // 1 = RETI, 0 = RET
+`define INSN_RETCC             9'b0110xx000
+`define INSN_CALL              9'b011001101
+`define INSN_CALLCC            9'b0110xx100    // Not that call/cc.
+`define INSN_JP_imm            9'b011000011
+`define INSN_JPCC_imm          9'b0110xx010
+`define INSN_ALU_A             9'b000xxx111
+`define INSN_JP_HL             9'b011101001
+`define INSN_JR_imm            9'b000011000
+`define INSN_JRCC_imm          9'b0001xx000
+`define INSN_INCDEC16          9'b000xxx011
+`define INSN_VOP_INTR          9'b011111100    // 0xFC is grabbed by the fetch if there is an interrupt pending.
+`define INSN_DI                        9'b011110011
+`define INSN_EI                        9'b011111011
+`define INSN_INCDEC_HL         9'b00011010x
+`define INSN_INCDEC_reg8       9'b000xxx10x
+`define INSN_LD8M_A            9'b0111x0000    // 1111 for ld A, x; 1110 for ld x, A; bit 1 specifies 16m8 or 8m8
+`define INSN_LD16M_A           9'b0111x1010    // 1111 for ld A, x; 1110 for ld x, A; bit 1 specifies 16m8 or 8m8
+`define INSN_LDBCDE_A          9'b0000xx010
+`define INSN_TWO_BYTE          9'b011001011    // prefix for two-byte opqodes
+`define INSN_ALU_EXT           9'b100xxxxxx
+`define INSN_BIT               9'b101xxxxxx
+`define INSN_RES               9'b110xxxxxx
+`define INSN_SET               9'b111xxxxxx
 
 `define INSN_cc_NZ             2'b00
 `define INSN_cc_Z              2'b01
 `define INSN_alu_CPL           3'b101
 `define INSN_alu_SCF           3'b110
 `define INSN_alu_CCF           3'b111
+`define INSN_alu_RLC           3'b000
+`define INSN_alu_RRC           3'b001
+`define INSN_alu_RL            3'b010
+`define INSN_alu_RR            3'b011
+`define INSN_alu_DA_SLA                3'b100
+`define INSN_alu_CPL_SRA       3'b101
+`define INSN_alu_SCF_SWAP      3'b110
+`define INSN_alu_CCF_SRL       3'b111
 
 `define EXEC_INC_PC            `_PC <= `_PC + 1;
 `define EXEC_NEXTADDR_PCINC    address <= `_PC + 1;
 `define EXEC_NEWCYCLE          begin newcycle <= 1; rd <= 1; wr <= 0; end
+`define EXEC_NEWCYCLE_TWOBYTE  begin newcycle <= 1; rd <= 1; wr <= 0; twobyte <= 1; end
 `define EXEC_WRITE(ad, da)     begin address <= (ad); wdata <= (da); wr <= 1; end end
 `define EXEC_READ(ad)          begin address <= (ad); rd <= 1; end end
 
@@ -126,7 +140,7 @@ module GBZ80Core(
        output reg buswr, output reg busrd,
        input irq, input [7:0] jaddr,
        output reg [1:0] state);
-       
+
 //     reg [1:0] state;                                        /* State within this bus cycle (see STATE_*). */
        reg [2:0] cycle;                                        /* Cycle for instructions. */
        
@@ -134,18 +148,77 @@ module GBZ80Core(
        
        reg [15:0] address;                             /* Address for the next bus operation. */
        
-       reg [7:0] opcode;                               /* Opcode from the current machine cycle. */
-       
+       reg [8:0] opcode;                               /* Opcode from the current machine cycle. */
+
        reg [7:0] rdata, wdata;         /* Read data from this bus cycle, or write data for the next. */
-       reg rd, wr, newcycle;
+       reg rd, wr, newcycle, twobyte;
        
        reg [7:0] tmp, tmp2;                    /* Generic temporary regs. */
        
        reg [7:0] buswdata;
        assign busdata = buswr ? buswdata : 8'bzzzzzzzz;
-       
+
        reg ie, iedelay;
-       
+
+       wire [7:0] rlc,rrc,rl,rr,sla,sra,swap,srl;
+       wire [3:0] rlcf,rrcf,rlf,rrf,slaf,sraf,swapf,srlf;
+       wire [7:0] alu_res;
+       wire [3:0] f_res;
+
+       assign rlc   = {tmp[6:0],tmp[7]};
+       assign rlcf  = {(tmp == 0 ? 1'b1 : 1'b0)
+                       ,2'b0,
+                       tmp[7]};
+
+       assign rrc   = {tmp[0],tmp[7:1]};
+       assign rrcf  = {(tmp == 0 ? 1'b1 : 1'b0),
+                       2'b0,
+                       tmp[0]};
+
+       assign rl    = {tmp[6:0],`_F[4]};
+       assign rlf   = {({tmp[6:0],`_F[4]} == 0 ? 1'b1 : 1'b0),
+                       2'b0,
+                       tmp[7]};
+
+       assign rr    = {`_F[4],tmp[7:1]};
+       assign rrf   = {({tmp[4],tmp[7:1]} == 0 ? 1'b1 : 1'b0),
+                       2'b0,
+                       tmp[0]};
+
+       assign sla   = {tmp[6:0],0};
+       assign slaf  = {(tmp[6:0] == 0 ? 1'b1 : 1'b0),
+                       2'b0,
+                       tmp[7]};
+
+       assign sra   = {tmp[7],tmp[7:1]};
+//     assign sraf  = {(tmp[7:1] == 0 ? 1'b1 : 1'b0),2'b0,tmp[0]};   now in assign srlf =
+
+       assign swap  = {tmp[3:0],tmp[7:4]};
+       assign swapf = {(tmp == 0 ? 1'b1 : 1'b0),
+                       3'b0};
+
+       assign srl   = {0,tmp[7:1]};
+       assign srlf  = {(tmp[7:1] == 0 ? 1'b1 : 1'b0),
+                       2'b0,
+                       tmp[0]};
+       assign sraf  = srlf;
+
+       /*  Y U Q  */
+       assign {alu_res,f_res} =
+               opcode[5] ? (
+                       opcode[4] ? (
+                               opcode[3] ? {srl,srlf} : {swap,swapf}
+                       ) : (
+                               opcode[3] ? {sra,sraf} : {sla,slaf}
+                       )
+               ) : (
+                       opcode[4] ? (
+                               opcode[3] ? {rr,rrf} : {rl,rlf}
+                       ) : (
+                               opcode[3] ? {rrc,rrcf} : {rlc,rlcf}
+                       )
+               );
+
        initial begin
                registers[ 0] <= 0;
                registers[ 1] <= 0;
@@ -172,13 +245,14 @@ module GBZ80Core(
                opcode <= 0;
                state <= `STATE_WRITEBACK;
                cycle <= 0;
+               twobyte <= 0;
        end
 
        always @(posedge clk)
                case (state)
                `STATE_FETCH: begin
                        if (newcycle) begin
-                               busaddress <= {registers[`REG_PCH], registers[`REG_PCL]};
+                               busaddress <= `_PC;
                                buswr <= 0;
                                busrd <= 1;
                        end else begin
@@ -192,10 +266,13 @@ module GBZ80Core(
                end
                `STATE_DECODE: begin
                        if (newcycle) begin
-                               if (ie && irq)
+                               if (twobyte) begin
+                                       opcode <= {1,busdata};
+                                       twobyte <= 0;
+                               end else if (ie && irq)
                                        opcode <= `INSN_VOP_INTR;
                                else
-                                       opcode <= busdata;
+                                       opcode <= {0,busdata};
                                rdata <= busdata;
                                newcycle <= 0;
                                cycle <= 0;
index 0a62af3..5ca51d6 100644 (file)
@@ -25,4 +25,6 @@
 `include "insn_incdec_reg8.v"
 `include "insn_ldm8_a.v"
 `include "insn_ldm16_a.v"
-`include "insn_ldbcde_a.v"
\ No newline at end of file
+`include "insn_ldbcde_a.v"
+`include "insn_two_byte.v"
+`include "insn_bit.v"
diff --git a/insn_bit.v b/insn_bit.v
new file mode 100644 (file)
index 0000000..c4b1fe5
--- /dev/null
@@ -0,0 +1,30 @@
+`ifdef EXECUTE
+       `INSN_BIT: begin
+               if ((opcode[2:0] == `INSN_reg_dHL) && (cycle == 0)) begin
+                       `EXEC_READ(`_HL)
+               end else if ((opcode[2:0] == `INSN_reg_dHL) && (cycle == 2)) begin
+                       `EXEC_NEWCYCLE
+               end else begin
+                       case (opcode[2:0])
+                       `INSN_reg_A:    tmp <= `_A;
+                       `INSN_reg_B:    tmp <= `_B;
+                       `INSN_reg_C:    tmp <= `_C;
+                       `INSN_reg_D:    tmp <= `_D;
+                       `INSN_reg_E:    tmp <= `_E;
+                       `INSN_reg_H:    tmp <= `_H;
+                       `INSN_reg_L:    tmp <= `_L;
+                       `INSN_reg_dHL:  tmp <= rdata;
+                       endcase
+                       if (opcode[2:0] != `INSN_reg_dHL) begin
+                               `EXEC_NEWCYCLE
+                       end
+               end
+       end
+`endif
+
+`ifdef WRITEBACK
+       `INSN_BIT: begin
+               if ((opcode[2:0] != `INSN_reg_dHL) || (cycle == 1))
+                       `_F <= {~tmp[opcode[5:3]], 2'b01, `_F[4:0]};
+       end
+`endif
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