moved a few urls to 8bitworkshop org

This commit is contained in:
Steven Hugg committed 2026-10-09 13:39:03 +02:00
1 parent 9de901133f
commit 9255226d81
4 files changed
+107 -107

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+1 -1
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@@ -2,7 +2,7 @@
"commonProperties": {},
"events": {
"error": {
"owner": "sehugg",
"owner": "8bitworkshop",
"comment": "A build tool, emulator, or extension failure, sent to 8bitworkshop.com/error.php. Gated on VS Code's telemetry.telemetryLevel through env.createTelemetryLogger; nothing is sent when telemetry is off. Uncaught errors from this extension use the same sender.",
"source": {
"classification": "SystemMetaData",
+7 -7
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@@ -6,7 +6,7 @@ A bouncing ball using absolute coordinates.
Note: This module uses different clock domains
and thus may be unstable on a FPGA.
See: https://github.com/sehugg/8bitworkshop/issues/23
See: https://github.com/8bitworkshop/8bitworkshop/issues/23
*/
module ball_absolute_top(clk, reset, hsync, vsync, rgb);
@@ -18,16 +18,16 @@ module ball_absolute_top(clk, reset, hsync, vsync, rgb);
wire display_on;
wire [8:0] hpos;
wire [8:0] vpos;
reg [8:0] ball_hpos; // ball current X position
reg [8:0] ball_vpos; // ball current Y position
reg [8:0] ball_horiz_move; // ball current X velocity
reg [8:0] ball_vert_move; // ball current Y velocity
localparam ball_horiz_initial = 128; // ball initial X position
localparam ball_vert_initial = 128; // ball initial Y position
localparam BALL_SIZE = 4; // ball size (in pixels)
// video sync generator
@@ -40,7 +40,7 @@ module ball_absolute_top(clk, reset, hsync, vsync, rgb);
.hpos(hpos),
.vpos(vpos)
);
// update horizontal timer
always @(posedge vsync or posedge reset)
begin
@@ -66,7 +66,7 @@ module ball_absolute_top(clk, reset, hsync, vsync, rgb);
begin
ball_horiz_move <= reset ? -2 : -ball_horiz_move;
end
// offset of ball position from video beam
wire [8:0] ball_hdiff = hpos - ball_hpos;
wire [8:0] ball_vdiff = vpos - ball_vpos;
+98 -98
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@@ -12,9 +12,9 @@
* https://github.com/Arlet/verilog-6502/
*
* Feel free to use this code in any project (commercial or not), as long as you
* keep this message, and the copyright notice. This code is provided "as is",
* without any warranties of any kind.
*
* keep this message, and the copyright notice. This code is provided "as is",
* without any warranties of any kind.
*
* Note that not all 6502 interface signals are supported (yet). The goal
* is to create an Acorn Atom model, and the Atom didn't use all signals on
* the main board.
@@ -22,12 +22,12 @@
* The data bus is implemented as separate read/write buses. Combine them
* on the output pads if external memory is required.
*
* Also see: https://github.com/sehugg/mango_one
* Also see: https://github.com/8bitworkshop/mango_one
*/
module cpu6502( clk, reset, AB, DI, DO, WE, IRQ, NMI, RDY );
input clk; // CPU clock
input clk; // CPU clock
input reset; // reset signal
output reg [15:0] AB; // address bus
input [7:0] DI; // data in, read bus
@@ -35,13 +35,13 @@ output [7:0] DO; // data out, write bus
output WE; // write enable
input IRQ; // interrupt request
input NMI; // non-maskable interrupt request
input RDY; // Ready signal. Pauses CPU when RDY=0
input RDY; // Ready signal. Pauses CPU when RDY=0
/*
* internal signals
*/
reg [15:0] PC; // Program Counter
reg [15:0] PC; // Program Counter
reg [7:0] ABL; // Address Bus Register LSB
reg [7:0] ABH; // Address Bus Register MSB
wire [7:0] ADD; // Adder Hold Register (registered in ALU)
@@ -50,7 +50,7 @@ reg [7:0] DIHOLD; // Hold for Data In
reg DIHOLD_valid; //
wire [7:0] DIMUX; //
reg [7:0] IRHOLD; // Hold for Instruction register
reg [7:0] IRHOLD; // Hold for Instruction register
reg IRHOLD_valid; // Valid instruction in IRHOLD
reg [7:0] AXYS[3:0]; // A, X, Y and S register file
@@ -70,10 +70,10 @@ reg [7:0] AI; // ALU Input A
reg [7:0] BI; // ALU Input B
wire [7:0] DI; // Data In
wire [7:0] IR; // Instruction register
reg [7:0] DO; // Data Out
reg [7:0] DO; // Data Out
reg WE; // Write Enable
reg CI; // Carry In
wire CO; // Carry Out
wire CO; // Carry Out
wire [7:0] PCH = PC[15:8];
wire [7:0] PCL = PC[7:0];
@@ -82,10 +82,10 @@ reg NMI_edge = 0; // captured NMI edge
reg [1:0] regsel; // Select A, X, Y or S register
wire [7:0] regfile = AXYS[regsel]; // Selected register output
parameter
parameter
SEL_A = 2'd0,
SEL_S = 2'd1,
SEL_X = 2'd2,
SEL_X = 2'd2,
SEL_Y = 2'd3;
/*
@@ -96,8 +96,8 @@ parameter
`ifdef SIM
wire [7:0] A = AXYS[SEL_A]; // Accumulator
wire [7:0] X = AXYS[SEL_X]; // X register
wire [7:0] Y = AXYS[SEL_Y]; // Y register
wire [7:0] S = AXYS[SEL_S]; // Stack pointer
wire [7:0] Y = AXYS[SEL_Y]; // Y register
wire [7:0] S = AXYS[SEL_S]; // Stack pointer
`endif
wire [7:0] P = { N, V, 2'b11, D, I, Z, C };
@@ -113,15 +113,15 @@ reg [5:0] state;
*/
reg PC_inc; // Increment PC
reg [15:0] PC_temp; // intermediate value of PC
reg [15:0] PC_temp; // intermediate value of PC
reg [1:0] src_reg; // source register index
reg [1:0] dst_reg; // destination register index
reg index_y; // if set, then Y is index reg rather than X
reg index_y; // if set, then Y is index reg rather than X
reg load_reg; // loading a register (A, X, Y, S) in this instruction
reg inc; // increment
reg write_back; // set if memory is read/modified/written
reg write_back; // set if memory is read/modified/written
reg load_only; // LDA/LDX/LDY instruction
reg store; // doing store (STA/STX/STY)
reg adc_sbc; // doing ADC/SBC
@@ -131,27 +131,27 @@ reg rotate; // doing rotate (no shift)
reg backwards; // backwards branch
reg cond_true; // branch condition is true
reg [2:0] cond_code; // condition code bits from instruction
reg shift_right; // Instruction ALU shift/rotate right
reg shift_right; // Instruction ALU shift/rotate right
reg alu_shift_right; // Current cycle shift right enable
reg [3:0] op; // Main ALU operation for instruction
reg [3:0] alu_op; // Current cycle ALU operation
reg adc_bcd; // ALU should do BCD style carry
reg [3:0] alu_op; // Current cycle ALU operation
reg adc_bcd; // ALU should do BCD style carry
reg adj_bcd; // results should be BCD adjusted
/*
/*
* some flip flops to remember we're doing special instructions. These
* get loaded at the DECODE state, and used later
*/
reg bit_ins; // doing BIT instruction
reg plp; // doing PLP instruction
reg php; // doing PHP instruction
reg php; // doing PHP instruction
reg clc; // clear carry
reg sec; // set carry
reg cld; // clear decimal
reg sed; // set decimal
reg cli; // clear interrupt
reg sei; // set interrupt
reg clv; // clear overflow
reg clv; // clear overflow
reg brk; // doing BRK
reg res; // in reset
@@ -173,17 +173,17 @@ parameter
* Microcode state machine. Basically, every addressing mode has its own
* path through the state machine. Additional information, such as the
* operation, source and destination registers are decoded in parallel, and
* kept in separate flops.
* kept in separate flops.
*/
parameter
ABS0 = 6'd0, // ABS - fetch LSB
parameter
ABS0 = 6'd0, // ABS - fetch LSB
ABS1 = 6'd1, // ABS - fetch MSB
ABSX0 = 6'd2, // ABS, X - fetch LSB and send to ALU (+X)
ABSX1 = 6'd3, // ABS, X - fetch MSB and send to ALU (+Carry)
ABSX2 = 6'd4, // ABS, X - Wait for ALU (only if needed)
BRA0 = 6'd5, // Branch - fetch offset and send to ALU (+PC[7:0])
BRA1 = 6'd6, // Branch - fetch opcode, and send PC[15:8] to ALU
BRA1 = 6'd6, // Branch - fetch opcode, and send PC[15:8] to ALU
BRA2 = 6'd7, // Branch - fetch opcode (if page boundary crossed)
BRK0 = 6'd8, // BRK/IRQ - push PCH, send S to ALU (-1)
BRK1 = 6'd9, // BRK/IRQ - push PCL, send S to ALU (-1)
@@ -194,9 +194,9 @@ parameter
INDX0 = 6'd14, // (ZP,X) - fetch ZP address, and send to ALU (+X)
INDX1 = 6'd15, // (ZP,X) - fetch LSB at ZP+X, calculate ZP+X+1
INDX2 = 6'd16, // (ZP,X) - fetch MSB at ZP+X+1
INDX3 = 6'd17, // (ZP,X) - fetch data
INDX3 = 6'd17, // (ZP,X) - fetch data
INDY0 = 6'd18, // (ZP),Y - fetch ZP address, and send ZP to ALU (+1)
INDY1 = 6'd19, // (ZP),Y - fetch at ZP+1, and send LSB to ALU (+Y)
INDY1 = 6'd19, // (ZP),Y - fetch at ZP+1, and send LSB to ALU (+Y)
INDY2 = 6'd20, // (ZP),Y - fetch data, and send MSB to ALU (+Carry)
INDY3 = 6'd21, // (ZP),Y) - fetch data (if page boundary crossed)
JMP0 = 6'd22, // JMP - fetch PCL and hold
@@ -215,15 +215,15 @@ parameter
READ = 6'd35, // Read memory for read/modify/write (INC, DEC, shift)
REG = 6'd36, // Read register for reg-reg transfers
RTI0 = 6'd37, // RTI - send S to ALU (+1)
RTI1 = 6'd38, // RTI - read P from stack
RTI1 = 6'd38, // RTI - read P from stack
RTI2 = 6'd39, // RTI - read PCL from stack
RTI3 = 6'd40, // RTI - read PCH from stack
RTI4 = 6'd41, // RTI - read PCH from stack
RTS0 = 6'd42, // RTS - send S to ALU (+1)
RTS1 = 6'd43, // RTS - read PCL from stack
RTS2 = 6'd44, // RTS - write PCL to ALU, read PCH
RTS1 = 6'd43, // RTS - read PCL from stack
RTS2 = 6'd44, // RTS - write PCL to ALU, read PCH
RTS3 = 6'd45, // RTS - load PC and increment
WRITE = 6'd46, // Write memory for read/modify/write
WRITE = 6'd46, // Write memory for read/modify/write
ZP0 = 6'd47, // Z-page - fetch ZP address
ZPX0 = 6'd48, // ZP, X - fetch ZP, and send to ALU (+X)
ZPX1 = 6'd49; // ZP, X - load from memory
@@ -311,14 +311,14 @@ always @*
JMP1,
JMPI1,
JSR3,
RTS3,
RTS3,
RTI4: PC_temp = { DIMUX, ADD };
BRA1: PC_temp = { ABH, ADD };
BRA2: PC_temp = { ADD, PCL };
BRK2: PC_temp = res ? 16'hfffc :
BRK2: PC_temp = res ? 16'hfffc :
NMI_edge ? 16'hfffa : 16'hfffe;
default: PC_temp = PC;
@@ -350,15 +350,15 @@ always @*
default: PC_inc = 0;
endcase
/*
/*
* Set new PC
*/
always @(posedge clk)
always @(posedge clk)
if( RDY )
PC <= PC_temp + {15'b0, PC_inc};
/*
* Address Generator
* Address Generator
*/
parameter
@@ -396,7 +396,7 @@ always @*
RTI2,
RTI3,
BRK2: AB = { STACKPAGE, ADD };
INDY1,
INDX1,
ZPX1,
@@ -418,7 +418,7 @@ always @*
* source of the address, such as the ALU or DI.
*/
always @(posedge clk)
if( state != PUSH0 && state != PUSH1 && RDY &&
if( state != PUSH0 && state != PUSH1 && RDY &&
state != PULL0 && state != PULL1 && state != PULL2 )
begin
ABL <= AB[7:0];
@@ -426,7 +426,7 @@ always @(posedge clk)
end
/*
* Data Out MUX
* Data Out MUX
*/
always @*
case( state )
@@ -481,8 +481,8 @@ always @*
case( state )
DECODE: write_register = load_reg & ~plp;
PULL1,
RTS2,
PULL1,
RTS2,
RTI3,
BRK3,
JSR0,
@@ -541,10 +541,10 @@ always @(posedge clk)
/*
* register select logic. This determines which of the A, X, Y or
* S registers will be accessed.
* S registers will be accessed.
*/
always @*
always @*
case( state )
INDY1,
INDX0,
@@ -552,7 +552,7 @@ always @*
ABSX0 : regsel = index_y ? SEL_Y : SEL_X;
DECODE : regsel = dst_reg;
DECODE : regsel = dst_reg;
BRK0,
BRK3,
@@ -565,8 +565,8 @@ always @*
RTI3,
RTS0,
RTS2 : regsel = SEL_S;
default: regsel = src_reg;
default: regsel = src_reg;
endcase
/*
@@ -596,10 +596,10 @@ always @*
case( state )
READ: alu_op = op;
BRA1: alu_op = backwards ? OP_SUB : OP_ADD;
BRA1: alu_op = backwards ? OP_SUB : OP_ADD;
FETCH,
REG : alu_op = op;
REG : alu_op = op;
DECODE,
ABS1: alu_op = 4'bx;
@@ -625,15 +625,15 @@ always @*
alu_shift_right = 0;
/*
* Sign extend branch offset.
* Sign extend branch offset.
*/
always @(posedge clk)
if( RDY )
backwards <= DIMUX[7];
/*
* ALU A Input MUX
/*
* ALU A Input MUX
*/
always @*
@@ -663,7 +663,7 @@ always @*
BRA0,
READ: AI = DIMUX;
BRA1: AI = ABH; // don't use PCH in case we're
BRA1: AI = ABH; // don't use PCH in case we're
FETCH: AI = load_only ? 0 : regfile;
@@ -694,11 +694,11 @@ always @*
BRK0,
BRK1,
BRK2,
PUSH0,
PUSH0,
PUSH1,
PULL0,
RTS0: BI = 8'h00;
BRA0: BI = PCL;
DECODE,
@@ -724,8 +724,8 @@ always @*
REG: CI = rotate ? C :
shift ? 0 : inc;
FETCH: CI = rotate ? C :
compare ? 1 :
FETCH: CI = rotate ? C :
compare ? 1 :
(shift | load_only) ? 0 : C;
PULL0,
@@ -735,7 +735,7 @@ always @*
RTS0,
RTS1,
INDY0,
INDX1: CI = 1;
INDX1: CI = 1;
default: CI = 0;
endcase
@@ -749,7 +749,7 @@ always @*
* Update C flag when doing ADC/SBC, shift/rotate, compare
*/
always @(posedge clk )
if( shift && state == WRITE )
if( shift && state == WRITE )
C <= CO;
else if( state == RTI2 )
C <= DIMUX[0];
@@ -768,8 +768,8 @@ always @(posedge clk )
* Update Z, N flags when writing A, X, Y, Memory, or when doing compare
*/
always @(posedge clk)
if( state == WRITE )
always @(posedge clk)
if( state == WRITE )
Z <= AZ;
else if( state == RTI2 )
Z <= DIMUX[1];
@@ -790,7 +790,7 @@ always @(posedge clk)
N <= ADD[7];
else if( (load_reg & (regsel != SEL_S)) | compare )
N <= AN;
end else if( state == FETCH && bit_ins )
end else if( state == FETCH && bit_ins )
N <= DIMUX[7];
/*
@@ -811,7 +811,7 @@ always @(posedge clk)
/*
* Update D flag
*/
always @(posedge clk )
always @(posedge clk )
if( state == RTI2 )
D <= DIMUX[3];
else if( state == DECODE ) begin
@@ -824,13 +824,13 @@ always @(posedge clk )
* Update V flag
*/
always @(posedge clk )
if( state == RTI2 )
if( state == RTI2 )
V <= DIMUX[6];
else if( state == DECODE ) begin
if( adc_sbc ) V <= AV;
if( clv ) V <= 0;
if( plp ) V <= ADD[6];
end else if( state == FETCH && bit_ins )
end else if( state == FETCH && bit_ins )
V <= DIMUX[6];
/*
@@ -871,21 +871,21 @@ always @(posedge clk or posedge reset)
if( reset )
state <= BRK0;
else if( RDY ) case( state )
DECODE :
DECODE :
casex ( IR )
8'b0000_0000: state <= BRK0;
8'b0010_0000: state <= JSR0;
8'b0010_1100: state <= ABS0; // BIT abs
8'b0100_0000: state <= RTI0; //
8'b0100_0000: state <= RTI0; //
8'b0100_1100: state <= JMP0;
8'b0110_0000: state <= RTS0;
8'b0110_1100: state <= JMPI0;
8'b0x00_1000: state <= PUSH0;
8'b0x10_1000: state <= PULL0;
8'b0xx1_1000: state <= REG; // CLC, SEC, CLI, SEI
8'b0xx1_1000: state <= REG; // CLC, SEC, CLI, SEI
8'b1xx0_00x0: state <= FETCH; // IMM
8'b1xx0_1100: state <= ABS0; // X/Y abs
8'b1xxx_1000: state <= REG; // DEY, TYA, ...
8'b1xxx_1000: state <= REG; // DEY, TYA, ...
8'bxxx0_0001: state <= INDX0;
8'bxxx0_01xx: state <= ZP0;
8'bxxx0_1001: state <= FETCH; // IMM
@@ -926,18 +926,18 @@ always @(posedge clk or posedge reset)
FETCH : state <= DECODE;
REG : state <= DECODE;
PUSH0 : state <= PUSH1;
PUSH1 : state <= DECODE;
PULL0 : state <= PULL1;
PULL1 : state <= PULL2;
PULL1 : state <= PULL2;
PULL2 : state <= DECODE;
JSR0 : state <= JSR1;
JSR1 : state <= JSR2;
JSR2 : state <= JSR3;
JSR3 : state <= FETCH;
JSR3 : state <= FETCH;
RTI0 : state <= RTI1;
RTI1 : state <= RTI2;
@@ -955,7 +955,7 @@ always @(posedge clk or posedge reset)
BRA2 : state <= DECODE;
JMP0 : state <= JMP1;
JMP1 : state <= DECODE;
JMP1 : state <= DECODE;
JMPI0 : state <= JMPI1;
JMPI1 : state <= JMP0;
@@ -983,7 +983,7 @@ always @(posedge clk)
8'b0xx01010, // ASLA, ROLA, LSRA, RORA
8'b0xxxxx01, // ORA, AND, EOR, ADC
8'b100x10x0, // DEY, TYA, TXA, TXS
8'b1010xxx0, // LDA/LDX/LDY
8'b1010xxx0, // LDA/LDX/LDY
8'b10111010, // TSX
8'b1011x1x0, // LDX/LDY
8'b11001010, // DEX
@@ -1017,14 +1017,14 @@ always @(posedge clk)
always @(posedge clk)
if( state == DECODE && RDY )
casex( IR )
8'b1011_1010: // TSX
src_reg <= SEL_S;
8'b1011_1010: // TSX
src_reg <= SEL_S;
8'b100x_x110, // STX
8'b100x_1x10, // TXA, TXS
8'b1110_xx00, // INX, CPX
8'b1100_1010: // DEX
src_reg <= SEL_X;
src_reg <= SEL_X;
8'b100x_x100, // STY
8'b1001_1000, // TYA
@@ -1035,7 +1035,7 @@ always @(posedge clk)
default: src_reg <= SEL_A;
endcase
always @(posedge clk)
always @(posedge clk)
if( state == DECODE && RDY )
casex( IR )
8'bxxx1_0001, // INDY
@@ -1062,7 +1062,7 @@ always @(posedge clk )
if( state == DECODE && RDY )
casex( IR )
8'b0xxx_x110, // ASL, ROL, LSR, ROR
8'b11xx_x110: // DEC/INC
8'b11xx_x110: // DEC/INC
write_back <= 1;
default: write_back <= 0;
@@ -1080,7 +1080,7 @@ always @(posedge clk )
always @(posedge clk )
if( state == DECODE && RDY )
casex( IR )
8'b111x_x110, // INC
8'b111x_x110, // INC
8'b11x0_1000: // INX, INY
inc <= 1;
@@ -1120,7 +1120,7 @@ always @(posedge clk )
casex( IR )
8'b11x0_0x00, // CPX, CPY (imm/zp)
8'b11x0_1100, // CPX, CPY (abs)
8'b110x_xx01: // CMP
8'b110x_xx01: // CMP
compare <= 1;
default: compare <= 0;
@@ -1132,17 +1132,17 @@ always @(posedge clk )
8'b01xx_xx10: // ROR, LSR
shift_right <= 1;
default: shift_right <= 0;
default: shift_right <= 0;
endcase
always @(posedge clk )
if( state == DECODE && RDY )
casex( IR )
8'b0x1x_1010, // ROL A, ROR A
8'b0x1x_x110: // ROR, ROL
8'b0x1x_x110: // ROR, ROL
rotate <= 1;
default: rotate <= 0;
default: rotate <= 0;
endcase
always @(posedge clk )
@@ -1151,15 +1151,15 @@ always @(posedge clk )
8'b00xx_xx10: // ROL, ASL
op <= OP_ROL;
8'b0010_x100: // BIT zp/abs
8'b0010_x100: // BIT zp/abs
op <= OP_AND;
8'b01xx_xx10: // ROR, LSR
op <= OP_A;
8'b1000_1000, // DEY
8'b1100_1010, // DEX
8'b110x_x110, // DEC
8'b1100_1010, // DEX
8'b110x_x110, // DEC
8'b11xx_xx01, // CMP, SBC
8'b11x0_0x00, // CPX, CPY (imm, zpg)
8'b11x0_1100: op <= OP_SUB;
@@ -1167,17 +1167,17 @@ always @(posedge clk )
8'b010x_xx01, // EOR
8'b00xx_xx01: // ORA, AND
op <= { 2'b11, IR[6:5] };
default: op <= OP_ADD;
default: op <= OP_ADD;
endcase
always @(posedge clk )
if( state == DECODE && RDY )
casex( IR )
8'b0010_x100: // BIT zp/abs
8'b0010_x100: // BIT zp/abs
bit_ins <= 1;
default: bit_ins <= 0;
default: bit_ins <= 0;
endcase
/*
* special instructions
@@ -1300,7 +1300,7 @@ always @* begin
2'b01: temp_BI = ~BI; // A-B
2'b10: temp_BI = temp_logic[7:0]; // A+A
2'b11: temp_BI = 0; // A+0
endcase
endcase
end
// HC9 is the half carry bit when doing BCD add
@@ -1319,7 +1319,7 @@ always @* begin
temp_h = temp_logic[8:4] + temp_BI[7:4] + {4'b0,temp_HC};
end
// calculate the flags
// calculate the flags
always @(posedge clk)
if( RDY ) begin
AI7 <= AI[7];
@@ -1344,7 +1344,7 @@ output wire [7:0] DO; // data out, write bus
output wire WE; // write enable
wire IRQ=0; // interrupt request
wire NMI=0; // non-maskable interrupt request
wire RDY=1; // Ready signal. Pauses CPU when RDY=0
wire RDY=1; // Ready signal. Pauses CPU when RDY=0
cpu6502 cpu( clk, reset, AB, DI, DO, WE, IRQ, NMI, RDY );
@@ -1352,7 +1352,7 @@ wire RDY=1; // Ready signal. Pauses CPU when RDY=0
begin
DI <= rom[AB[3:0]];
end
reg [7:0] rom[0:15];
// LDY #$13
// .loop: DEY
@@ -1366,5 +1366,5 @@ wire RDY=1; // Ready signal. Pauses CPU when RDY=0
rom[4] = 8'hfd;
rom[5] = 8'h00;
end
endmodule
+1 -1
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@@ -3,7 +3,7 @@
//var IDEURL = 'https://8bitworkshop.com/dev/';
var IDEURL = 'http://localhost:8000/'
var REPO = 'sehugg/happy2020'
var REPO = '8bitworkshop/happy2020'
var PLATFORM = 'astrocade'
var FILE = 'happy2020.c'
var PRESETFILE = 'hello.c'