Subversion Repositories s80186

// Copyright Jamie Iles, 2017

//

// This file is part of s80x86.

//

// s80x86 is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

//

// s80x86 is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

//

// You should have received a copy of the GNU General Public License

// along with s80x86.  If not, see .

// Multiplicand in TEMP, multiplier in MDR

mulf6_reg:

    width W8, a_sel RA, alu_op SELA, mdr_write, ra_sel AL, jmp do_mul8;

mulf6_mem:

    width W8, segment DS, mem_read, ra_sel AL, jmp do_mul8;

do_mul8:

    width W8, a_sel RA, alu_op SELA, tmp_wr_en;

    // 8-bit multiplication yields a 16-bit result so move the result into

    // TEMP to later transfer to AX as a 16-bit operation.

    width W8, a_sel MDR, b_sel TEMP, alu_op MUL, update_flags ZF OF CF,

        tmp_wr_en;

    b_sel TEMP, alu_op SELB, rd_sel_source MICROCODE_RD_SEL, rd_sel AX,

        next_instruction;

// Multiplicand in TEMP, multiplier in MDR

mulf7_reg:

    a_sel RA, alu_op SELA, mdr_write, ra_sel AX, jmp do_mul16;

mulf7_mem:

    segment DS, mem_read, ra_sel AX, jmp do_mul16;

do_mul16:

    a_sel RA, alu_op SELA, tmp_wr_en;

    a_sel MDR, b_sel TEMP, alu_op MUL, update_flags ZF OF CF,

        tmp_wr_sel Q_HIGH, tmp_wr_en, rd_sel_source MICROCODE_RD_SEL,

        rd_sel AX;

    b_sel TEMP, alu_op SELB, rd_sel_source MICROCODE_RD_SEL, rd_sel DX,

        next_instruction;

// imultiplicand in TEMP, imultiplier in MDR

imulf6_reg:

    width W8, a_sel RA, alu_op SELA, mdr_write, ra_sel AL, jmp do_imul8;

imulf6_mem:

    width W8, segment DS, mem_read, ra_sel AL, jmp do_imul8;

do_imul8:

    width W8, a_sel RA, alu_op SELA, tmp_wr_en;

    // 8-bit imultiplication yields a 16-bit result so move the result into

    // TEMP to later transfer to AX as a 16-bit operation.

    width W8, a_sel MDR, b_sel TEMP, alu_op IMUL, update_flags ZF OF CF,

        tmp_wr_en;

    b_sel TEMP, alu_op SELB, rd_sel_source MICROCODE_RD_SEL, rd_sel AX,

        next_instruction;

// imultiplicand in TEMP, imultiplier in MDR

imulf7_reg:

    a_sel RA, alu_op SELA, mdr_write, ra_sel AX, jmp do_imul16;

imulf7_mem:

    segment DS, mem_read, ra_sel AX, jmp do_imul16;

do_imul16:

    a_sel RA, alu_op SELA, tmp_wr_en;

    a_sel MDR, b_sel TEMP, alu_op IMUL, update_flags ZF OF CF,

        tmp_wr_sel Q_HIGH, tmp_wr_en, rd_sel_source MICROCODE_RD_SEL,

        rd_sel AX;

    b_sel TEMP, alu_op SELB, rd_sel_source MICROCODE_RD_SEL, rd_sel DX,

        next_instruction;

.at 0x6b;

    modrm_start, mar_write mar_wr_sel EA, jmp imul_6b;

.auto_address;

imul_6b:

    width W8, read_immed;

    ra_modrm_rm_reg, segment DS, jmp_rm_reg_mem imul6b_reg;

imul6b_reg:

    a_sel RA, b_sel IMMEDIATE, alu_op IMUL, update_flags ZF OF CF,

        rd_sel_source MODRM_REG, next_instruction;

imul6b_mem:

    segment DS, mem_read;

    a_sel MDR, b_sel IMMEDIATE, alu_op IMUL, update_flags ZF OF CF,

        rd_sel_source MODRM_REG, next_instruction;

.at 0x69;

    modrm_start, mar_write mar_wr_sel EA, jmp imul_69;

.auto_address;

imul_69:

    // Now that we have the immediate, everything is the same as opcode 6b

    read_immed, ra_modrm_rm_reg, segment DS, jmp_rm_reg_mem imul6b_reg;