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add block Cx and Fx

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implement 2CMPL and ADD
This commit is contained in:
Raphael Jacquot 2019-03-15 17:17:19 +01:00
parent e6e3bb2325
commit c953bc82f4
3 changed files with 72 additions and 1 deletions
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2
saturn_bus.v
View file

@ -237,7 +237,7 @@ always @(posedge i_clk) begin
end
`ifdef SIM
if (cycle_ctr == 265) begin
if (cycle_ctr == 285) begin
bus_halt <= 1'b1;
$display("BUS %0d: [%d] enough cycles for now", phase, cycle_ctr);
end

21
saturn_control_unit.v
View file

@ -724,6 +724,9 @@ always @(posedge i_clk) begin
endcase
/* need to prepare the carry here */
case (alu_opcode)
`ALU_OP_ADD: alu_prep_carry <= (alu_prep_pos == alu_ptr_begin) ? 1'b0 : alu_prep_carry;
endcase
if (alu_prep_pos == alu_ptr_end) begin
alu_prep_done <= 1'b1;
@ -753,6 +756,16 @@ always @(posedge i_clk) begin
alu_calc_res_1_val <= alu_prep_src_2_val;
alu_calc_res_2_val <= alu_prep_src_1_val;
end
`ALU_OP_2CMPL: alu_calc_res_1_val <= ~alu_prep_src_1_val + 4'h1;
`ALU_OP_ADD:
begin
$display("ALU_CALC %0d: [%d] add | s1 %b | s2 %b | c %b | res %b | nc %b", i_phase, i_cycle_ctr,
alu_prep_src_1_val, alu_prep_src_2_val, {3'b0, alu_prep_carry},
alu_prep_src_1_val + alu_prep_src_2_val + {3'b0, alu_prep_carry},
alu_prep_src_1_val[3] && alu_prep_src_2_val[3] );
alu_calc_res_1_val <= alu_prep_src_1_val + alu_prep_src_2_val + {3'b0, alu_prep_carry};
alu_calc_carry <= alu_prep_src_1_val[3] && alu_prep_src_2_val[3];
end
default: $display("ALU_CALC %0d: [%d] unhandled opcode %0d", i_phase, i_cycle_ctr, alu_opcode);
endcase
@ -799,6 +812,14 @@ always @(posedge i_clk) begin
default: $display("ALU_SAVE %0d: [%d] exch: src_2 register %0d not supported", i_phase, i_cycle_ctr, alu_reg_src_2);
endcase
alu_prep_carry <= alu_calc_carry;
case (alu_opcode)
// this may not be correct, need to check on the HP 49G
`ALU_OP_2CMPL: reg_CARRY <= reg_CARRY || ( | alu_calc_res_1_val);
`ALU_OP_ADD : reg_CARRY <= alu_calc_carry;
default: begin end
endcase
if (alu_save_pos == alu_ptr_end) begin
alu_save_done <= 1'b1;
alu_save_run <= 1'b0;

50
saturn_inst_decoder.v
View file

@ -147,7 +147,9 @@ reg [0:0] block_84x_85x;
reg [0:0] block_Ax;
reg [0:0] block_Aax;
reg [0:0] block_Abx;
reg [0:0] block_Cx;
reg [0:0] block_Dx;
reg [0:0] block_Fx;
reg [0:0] block_JUMP;
reg [0:0] block_LOAD;
@ -200,7 +202,9 @@ initial begin
block_Ax = 1'b0;
block_Aax = 1'b0;
block_Abx = 1'b0;
block_Cx = 1'b0;
block_Dx = 1'b0;
block_Fx = 1'b0;
block_JUMP = 1'b0;
block_LOAD = 1'b0;
@ -280,7 +284,9 @@ always @(posedge i_clk) begin
block_FIELDS <= 1'b1;
fields_table <= `FT_A_B;
end
4'hC: block_Cx <= 1'b1;
4'hD: block_Dx <= 1'b1;
4'hF: block_Fx <= 1'b1;
default:
begin
$display("invalid instruction");
@ -524,6 +530,27 @@ always @(posedge i_clk) begin
block_Abx <= 1'b0;
end
if (block_Cx) begin
$display("DECODER %0d: [%d] block_Cx %h", i_phase, i_cycle_ctr, i_nibble);
o_instr_type <= `INSTR_TYPE_ALU;
o_alu_field <= `FT_FIELD_A;
o_alu_ptr_begin <= 4'h0;
o_alu_ptr_end <= 4'h4;
o_alu_opcode <= (i_nibble[3] && i_nibble[2]) ? `ALU_OP_DEC : `ALU_OP_ADD;
o_alu_reg_dest <= (i_nibble[3] && !i_nibble[2]) ? regs_BCAC : regs_ABCD;
o_alu_reg_src_1 <= (i_nibble[3] && !i_nibble[2]) ? regs_BCAC : regs_ABCD;
case ({i_nibble[3], i_nibble[2]})
2'b00: o_alu_reg_src_2 <= regs_BCAC;
2'b01,
2'b10: o_alu_reg_src_2 <= regs_ABCD;
2'b11: o_alu_reg_src_2 <= `ALU_REG_NONE;
endcase
o_instr_decoded <= 1'b1;
o_instr_execute <= 1'b1;
decode_started <= 1'b0;
block_Cx <= 1'b0;
end
if (block_Dx) begin
$display("DECODER %0d: [%d] block_Dx %h", i_phase, i_cycle_ctr, i_nibble);
o_instr_type <= `INSTR_TYPE_ALU;
@ -564,6 +591,27 @@ always @(posedge i_clk) begin
block_Dx <= 1'b0;
end
if (block_Fx) begin
$display("DECODER %0d: [%d] block_Fx %h", i_phase, i_cycle_ctr, i_nibble);
o_instr_type <= `INSTR_TYPE_ALU;
o_alu_field <= `FT_FIELD_A;
o_alu_ptr_begin <= 4'h0;
o_alu_ptr_end <= 4'h4;
o_alu_reg_dest <= regs_ABCD;
o_alu_reg_src_1 <= regs_ABCD;
o_alu_reg_src_2 <= `ALU_REG_NONE;
case ({i_nibble[3], i_nibble[2]})
2'b00: o_alu_opcode <= `ALU_OP_SHL;
2'b01: o_alu_opcode <= `ALU_OP_SHR;
2'b10: o_alu_opcode <= `ALU_OP_2CMPL;
2'b11: o_alu_opcode <= `ALU_OP_1CMPL;
endcase
o_instr_decoded <= 1'b1;
o_instr_execute <= 1'b1;
decode_started <= 1'b0;
block_Fx <= 1'b0;
end
/* special cases */
if (block_JUMP) begin
@ -717,7 +765,9 @@ always @(posedge i_clk) begin
block_Ax <= 1'b0;
block_Aax <= 1'b0;
block_Abx <= 1'b0;
block_Cx <= 1'b0;
block_Dx <= 1'b0;
block_Fx <= 1'b0;
block_JUMP <= 1'b0;
block_LOAD <= 1'b0;