mirror of
https://github.com/Gehstock/Mist_FPGA.git
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90 lines
2.2 KiB
Plaintext
90 lines
2.2 KiB
Plaintext
// Copyright Jamie Iles, 2017
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//
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// This file is part of s80x86.
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//
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// s80x86 is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// s80x86 is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with s80x86. If not, see <http://www.gnu.org/licenses/>.
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.at 0xe9;
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a_sel IP, b_sel IMMEDIATE, alu_op ADD, load_ip,
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next_instruction;
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.at 0xea;
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b_sel IMMEDIATE, alu_op SELB, load_ip, jmp jmpea;
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.auto_address;
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jmpea:
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b_sel IMMEDIATE2, alu_op SELB, segment_wr_en,
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segment_force, segment CS, next_instruction;
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.at 0xeb;
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a_sel IP, b_sel IMMEDIATE, alu_op ADD, load_ip,
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next_instruction;
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jmpff_indirect_intra_reg:
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a_sel RA, alu_op SELA, load_ip,
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next_instruction;
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jmpff_indirect_intra_mem:
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segment DS, mem_read;
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a_sel MDR, alu_op SELA, load_ip,
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next_instruction;
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jmpff_indirect_inter_reg:
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next_instruction;
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jmpff_indirect_inter_mem:
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segment DS, mem_read;
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a_sel MDR, alu_op SELA, load_ip;
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immediate 0x2, a_sel MAR, b_sel IMMEDIATE, alu_op ADD,
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mar_wr_sel Q, mar_write, segment DS;
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segment DS, mem_read;
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a_sel MDR, alu_op SELA, segment_wr_en,
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segment_force, segment CS, next_instruction;
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// JCXZ
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.at 0xe3;
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rb_cl, jmp jcxz;
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.auto_address;
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jcxz:
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jmp_rb_zero jcxz_taken;
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next_instruction;
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jcxz_taken:
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a_sel IP, b_sel IMMEDIATE, alu_op ADD, load_ip, next_instruction;
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#define JUMP(opcode) \
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.at opcode; \
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jmp test_jump
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JUMP(0x70);
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JUMP(0x71);
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JUMP(0x72);
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JUMP(0x73);
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JUMP(0x74);
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JUMP(0x75);
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JUMP(0x76);
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JUMP(0x77);
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JUMP(0x78);
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JUMP(0x79);
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JUMP(0x7a);
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JUMP(0x7b);
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JUMP(0x7c);
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JUMP(0x7d);
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JUMP(0x7e);
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JUMP(0x7f);
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.auto_address;
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test_jump:
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jmp_if_taken jmp_taken;
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next_instruction;
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jmp_taken:
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a_sel IP, b_sel IMMEDIATE, alu_op ADD, load_ip, next_instruction;
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