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[/] [ao486/] [trunk/] [rtl/] [ao486/] [commands/] [CMD_SHxD.txt] - Rev 8

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<defines>
`define CMD_SHxD        #AUTOGEN_NEXT_CMD_MOD2
`define CMD_SHLD        #AUTOGEN_NEXT_CMD_LIKE_PREV
`define CMD_SHRD        #AUTOGEN_NEXT_CMD

`define CMDEX_SHxD_implicit     4'd0
`define CMDEX_SHxD_modregrm_imm 4'd1
</defines>

<decode>
(dec_ready_2byte_modregrm && decoder[7:0] == 8'hA5) || (dec_ready_2byte_modregrm_imm && decoder[7:0] == 8'hA4)
`CMD_SHLD
IF(decoder[0]); SET(dec_cmdex, `CMDEX_SHxD_implicit); ELSE(); SET(dec_cmdex, `CMDEX_SHxD_modregrm_imm); ENDIF();
IF(decoder[0] == 1'b0); SET(consume_modregrm_imm); ELSE(); SET(consume_modregrm_one); ENDIF();
</decode>

<decode>
(dec_ready_2byte_modregrm && decoder[7:0] == 8'hAD) || (dec_ready_2byte_modregrm_imm && decoder[7:0] == 8'hAC)
`CMD_SHRD
IF(decoder[0]); SET(dec_cmdex, `CMDEX_SHxD_implicit); ELSE(); SET(dec_cmdex, `CMDEX_SHxD_modregrm_imm); ENDIF();
IF(decoder[0] == 1'b0); SET(consume_modregrm_imm); ELSE(); SET(consume_modregrm_one); ENDIF();
</decode>

<read>
IF({ rd_cmd[6:1], 1'd0 } == `CMD_SHxD && rd_cmdex != `CMDEX_SHxD_implicit);
    
    SET(rd_src_is_reg);
    
    SET(rd_req_eflags);
    
    // dst: reg, src: imm
    IF(rd_modregrm_mod == 2'b11);
        
        SET(rd_dst_is_rm);
            
        SET(rd_req_rm);
    
        IF(rd_mutex_busy_modregrm_rm || rd_mutex_busy_modregrm_reg); SET(rd_waiting); ENDIF();
    ENDIF();

    // dst: memory, src: imm or 1
    IF(rd_modregrm_mod != 2'b11);
        
        SET(rd_dst_is_memory);
            
        SET(rd_req_memory);
    
        IF(rd_mutex_busy_memory || rd_mutex_busy_modregrm_reg); SET(rd_waiting);
        ELSE();
            SET(read_rmw_virtual);

            IF(~(read_for_rd_ready)); SET(rd_waiting); ENDIF();
        ENDIF();
    ENDIF();
ENDIF();
</read>

<read>
IF({ rd_cmd[6:1], 1'd0 } == `CMD_SHxD && rd_cmdex == `CMDEX_SHxD_implicit);
        
    SET(rd_src_is_reg);
    
    SET(rd_req_eflags);
    
    // dst: reg, src: CL
    IF(rd_modregrm_mod == 2'b11);
        
        SET(rd_dst_is_rm);
            
        SET(rd_req_rm);
            
        IF(rd_mutex_busy_modregrm_rm || rd_mutex_busy_ecx || rd_mutex_busy_modregrm_reg); SET(rd_waiting); ENDIF();
    ENDIF();

    // dst: memory, src: imm or 1
    IF(rd_modregrm_mod != 2'b11);
            
        SET(rd_dst_is_memory);
            
        SET(rd_req_memory);
    
        IF(rd_mutex_busy_memory || rd_mutex_busy_ecx || rd_mutex_busy_modregrm_reg); SET(rd_waiting);
        ELSE();
            SET(read_rmw_virtual);

            IF(~(read_for_rd_ready)); SET(rd_waiting); ENDIF();
        ENDIF();
    ENDIF();
ENDIF();
</read>

<execute>
IF({ exe_cmd[6:1], 1'd0 } == `CMD_SHxD);
    
    SET(exe_result, e_shift_result);
    SET(exe_result_signals, { e_shift_no_write, e_shift_oszapc_update, e_shift_cf_of_update, e_shift_oflag, e_shift_cflag });

ENDIF();
</execute>

<write>
IF({ wr_cmd[6:1], 1'd0 } == `CMD_SHxD);

    // result_signals
    // { e_shift_no_write, e_shift_oszapc_update, e_shift_cf_of_update, e_shift_oflag, e_shift_cflag }

    IF(~(result_signals[4])); //e_shift_no_write
        IF(wr_dst_is_memory && ~(write_for_wr_ready)); SET(wr_waiting); ENDIF();
    
        SET(write_regrm,         wr_dst_is_rm);
        SET(write_rmw_virtual,   wr_dst_is_memory);
    ENDIF();
    
    IF(result_signals[3]); //e_shift_oszapc_update
        SAVE(zflag, zflag_result);
        SAVE(sflag, sflag_result);
        SAVE(pflag, pflag_result);
        SAVE(aflag, aflag_arith);
    ENDIF();
    
    IF(result_signals[2]); //e_shift_cf_of_update
        SAVE(cflag, result_signals[0]);
        SAVE(oflag, result_signals[1]);
    ENDIF();
ENDIF();  
</write>

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