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 .

.at 0xae;

    jmp scasb, ra_sel DI;

.auto_address;

scasb:

    ra_sel DI, a_sel RA, alu_op SELA, mar_wr_sel Q, mar_write, rb_cl,

        jmp_if_not_rep scasb_no_rep;

scasb_rep_loop:

    ra_sel CX, jmp_rb_zero scasb_done;

    ra_sel DI, a_sel RA, b_sel IMMEDIATE, immediate 0x1, alu_op SUB,

        rd_sel_source MICROCODE_RD_SEL, rd_sel CX, segment ES, segment_force;

scasb_no_rep:

    width W8, segment ES, segment_force, mem_read, ra_sel AL,

        a_sel RA, alu_op SELA, tmp_wr_en;

    width W8, a_sel MDR, b_sel TEMP, alu_op SUBREV,

        update_flags OF SF ZF CF PF AF, jmp_if_not_rep scasb_done_no_rep;

    a_sel MAR, b_sel IMMEDIATE, immediate 0x1, alu_op NEXT,

        rd_sel_source MICROCODE_RD_SEL, rd_sel DI, mar_write, mar_wr_sel Q,

        rb_cl, ext_int_yield, jmp_if_rep_not_complete scasb_rep_loop,

        segment ES, segment_force;

scasb_done:

    next_instruction;

scasb_done_no_rep:

    a_sel MAR, b_sel IMMEDIATE, immediate 0x1, alu_op NEXT,

        rd_sel_source MICROCODE_RD_SEL, rd_sel DI, next_instruction;

.at 0xaf;

    jmp scasw, ra_sel DI;

.auto_address;

scasw:

    ra_sel DI, a_sel RA, alu_op SELA, mar_wr_sel Q, mar_write,

        rb_cl, jmp_if_not_rep scasw_no_rep;

scasw_rep_loop:

    ra_sel CX, jmp_rb_zero scasw_done;

    ra_sel DI, a_sel RA, b_sel IMMEDIATE, immediate 0x1, alu_op SUB,

        rd_sel_source MICROCODE_RD_SEL, rd_sel CX, segment ES, segment_force;

scasw_no_rep:

    segment ES, segment_force, mem_read, ra_sel AX, a_sel RA, alu_op SELA,

        tmp_wr_en;

    a_sel MDR, b_sel TEMP, alu_op SUBREV, update_flags OF SF ZF CF PF AF,

        jmp_if_not_rep scasw_done_no_rep;

    a_sel MAR, b_sel IMMEDIATE, immediate 0x2, alu_op NEXT,

        rd_sel_source MICROCODE_RD_SEL, rd_sel DI, mar_write, mar_wr_sel Q,

        rb_cl, ext_int_yield, jmp_if_rep_not_complete scasw_rep_loop,

        segment ES, segment_force;

scasw_done:

    next_instruction;

scasw_done_no_rep:

    a_sel MAR, b_sel IMMEDIATE, immediate 0x2, alu_op NEXT,

        rd_sel_source MICROCODE_RD_SEL, rd_sel DI, next_instruction;