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Arlet 65C02 WIP: Implement JMP (,X)

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Change-Id: I4a216b446ae23e05138d574875dbe54cccc052eb
This commit is contained in:
David Banks
2016-08-01 12:01:04 +01:00
parent 05e5f633f7
commit db83fd4af9
1 changed files with 24 additions and 1 deletions
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25
cpu_65c02.v
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@@ -225,7 +225,10 @@ parameter
ZP0 = 6'd47, // Z-page - fetch ZP address ZP0 = 6'd47, // Z-page - fetch ZP address
ZPX0 = 6'd48, // ZP, X - fetch ZP, and send to ALU (+X) ZPX0 = 6'd48, // ZP, X - fetch ZP, and send to ALU (+X)
ZPX1 = 6'd49, // ZP, X - load from memory ZPX1 = 6'd49, // ZP, X - load from memory
IND0 = 6'd50; // (ZP) - fetch ZP address, and send to ALU (+0) IND0 = 6'd50, // (ZP) - fetch ZP address, and send to ALU (+0)
JMPIX0 = 6'd51, // JMP (,X)- fetch LSB and send to ALU (+X)
JMPIX1 = 6'd52, // JMP (,X)- fetch MSB and send to ALU (+Carry)
JMPIX2 = 6'd53; // JMP (,X)- Wait for ALU (only if needed)
`ifdef SIM `ifdef SIM
@@ -287,6 +290,10 @@ always @*
JMP1: statename = "JMP1"; JMP1: statename = "JMP1";
JMPI0: statename = "JMPI0"; JMPI0: statename = "JMPI0";
JMPI1: statename = "JMPI1"; JMPI1: statename = "JMPI1";
JMPIX0: statename = "JMPIX0";
JMPIX1: statename = "JMPIX1";
JMPIX2: statename = "JMPIX2";
endcase endcase
//always @( PC ) //always @( PC )
@@ -310,12 +317,14 @@ always @*
JMP1, JMP1,
JMPI1, JMPI1,
JMPIX1,
JSR3, JSR3,
RTS3, RTS3,
RTI4: PC_temp = { DIMUX, ADD }; RTI4: PC_temp = { DIMUX, ADD };
BRA1: PC_temp = { ABH, ADD }; BRA1: PC_temp = { ABH, ADD };
JMPIX2,
BRA2: PC_temp = { ADD, PCL }; BRA2: PC_temp = { ADD, PCL };
BRK2: PC_temp = res ? 16'hfffc : BRK2: PC_temp = res ? 16'hfffc :
@@ -335,6 +344,8 @@ always @*
PC_inc = 1; PC_inc = 1;
ABS0, ABS0,
JMPIX0,
JMPIX2,
ABSX0, ABSX0,
FETCH, FETCH,
BRA0, BRA0,
@@ -345,6 +356,8 @@ always @*
RTI4, RTI4,
RTS3: PC_inc = 1; RTS3: PC_inc = 1;
JMPIX1: PC_inc = ~CO; // Don't increment PC if we are going to go through JMPIX2
BRA1: PC_inc = CO ^~ backwards; BRA1: PC_inc = CO ^~ backwards;
default: PC_inc = 0; default: PC_inc = 0;
@@ -367,6 +380,7 @@ parameter
always @* always @*
case( state ) case( state )
JMPIX1,
ABSX1, ABSX1,
INDX3, INDX3,
INDY2, INDY2,
@@ -377,6 +391,7 @@ always @*
BRA2, BRA2,
INDY3, INDY3,
JMPIX2,
ABSX2: AB = { ADD, ABL }; ABSX2: AB = { ADD, ABL };
BRA1: AB = { ABH, ADD }; BRA1: AB = { ABH, ADD };
@@ -549,6 +564,7 @@ always @*
INDY1, INDY1,
INDX0, INDX0,
ZPX0, ZPX0,
JMPIX0,
ABSX0 : regsel = index_y ? SEL_Y : SEL_X; ABSX0 : regsel = index_y ? SEL_Y : SEL_X;
@@ -649,6 +665,7 @@ always @*
REG, REG,
ZPX0, ZPX0,
INDX0, INDX0,
JMPIX0,
ABSX0, ABSX0,
RTI0, RTI0,
RTS0, RTS0,
@@ -716,6 +733,7 @@ always @*
case( state ) case( state )
INDY2, INDY2,
BRA1, BRA1,
JMPIX1,
ABSX1: CI = CO; ABSX1: CI = CO;
DECODE, DECODE,
@@ -896,6 +914,7 @@ always @(posedge clk or posedge reset)
8'b0100_1100: state <= JMP0; 8'b0100_1100: state <= JMP0;
8'b0110_0000: state <= RTS0; 8'b0110_0000: state <= RTS0;
8'b0110_1100: state <= JMPI0; 8'b0110_1100: state <= JMPI0;
8'b0111_1100: state <= JMPIX0;
8'b0x00_1000: state <= PUSH0; 8'b0x00_1000: state <= PUSH0;
8'b0x10_1000: state <= PULL0; 8'b0x10_1000: state <= PULL0;
8'b0xx1_1000: state <= REG; // CLC, SEC, CLI, SEI 8'b0xx1_1000: state <= REG; // CLC, SEC, CLI, SEI
@@ -936,6 +955,10 @@ always @(posedge clk or posedge reset)
ABSX1 : state <= (CO | store | write_back) ? ABSX2 : FETCH; ABSX1 : state <= (CO | store | write_back) ? ABSX2 : FETCH;
ABSX2 : state <= write_back ? READ : FETCH; ABSX2 : state <= write_back ? READ : FETCH;
JMPIX0 : state <= JMPIX1;
JMPIX1 : state <= CO ? JMPIX2 : JMP0;
JMPIX2 : state <= JMP0;
IND0 : state <= INDX1; IND0 : state <= INDX1;
INDX0 : state <= INDX1; INDX0 : state <= INDX1;