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add or substract constant do D0 and D1

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This commit is contained in:
Raphael Jacquot 2019-02-10 13:39:56 +01:00
parent bde3e1a027
commit efd93e4a95
4 changed files with 27 additions and 1 deletions
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1
decstates.v
View file

@ -11,6 +11,7 @@
`define DEC_15X_FIELD 12'h151 // 15XX
`define DEC_MEMAXX 12'h152 // 1[45]x[y]
`define DEC_MEMAXX_END 12'h153
`define DEC_PTR_MATH 12'h160 // 1[678C]n D[01]=D[01][+-] (n+1)
`define DEC_D0_EQ_4N 12'h1A0 // 1B
`define DEC_D0_EQ_5N 12'h1B0 // 1B
`define DEC_D0_EQ_LOOP 12'h1B1 // 1Bxxxxx (exec)

18
opcodes/1[678C]n_D[01]_math_n.v Normal file
View file

@ -0,0 +1,18 @@
/******************************************************************************
*1[678C] D[01]=D[01][+-] (n+1)
*
*
*/
`DEC_PTR_MATH: begin
case ({t_ptr, t_add_sub})
2'b00: {Carry, D0} <= D0 + (nb_in + 1);
2'b01: {Carry, D0} <= D0 - (nb_in + 1);
2'b10: {Carry, D1} <= D1 + (nb_in + 1);
2'b11: {Carry, D1} <= D1 - (nb_in + 1);
endcase
decstate <= `DEC_START;
`ifdef SIM
$display("%5h D%b=D%b%s\t%2d", inst_start_PC, t_ptr, t_ptr, t_add_sub?"-":"+", nb_in+1);
`endif
end

7
opcodes/1x.v
View file

@ -11,12 +11,17 @@
4'h3: decstate <= `DEC_13X;
4'h4: decstate <= `DEC_14X;
4'h5: decstate <= `DEC_15X;
4'h6, 4'h7, 4'h8, 4'hC: begin
t_ptr <= (nb_in[0] & nb_in[1]) | (nb_in[2] & nb_in[3]);
t_add_sub <= nb_in[3];
decstate <= `DEC_PTR_MATH;
end
4'hA: decstate <= `DEC_D0_EQ_4N;
4'hB: decstate <= `DEC_D0_EQ_5N;
4'hE: decstate <= `DEC_D1_EQ_4N;
4'hF: decstate <= `DEC_D1_EQ_5N;
default: begin
$display("ERROR : DEC_1X");
$display("ERROR : DEC_1X %h", nb_in);
decode_error <= 1;
end
endcase

2
saturn_core.v
View file

@ -118,6 +118,7 @@ reg [19:0] add_out;
// temporary stuff
reg t_set_test;
reg t_set_test_val;
reg t_add_sub;
// processor registers
reg [19:0] PC;
@ -395,6 +396,7 @@ always @(posedge dec_strobe) begin
`include "opcodes/1x.v"
`include "opcodes/13x_ptr_and_AC.v"
`include "opcodes/1[45]_memaccess.v"
`include "opcodes/1[678C]n_D[01]_math_n.v"
`include "opcodes/1[ABEF]nnnnn_D[01]_EQ_5n.v"
`include "opcodes/2n_P_EQ_n.v"
`include "opcodes/3n[x...]_LC.v"