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

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<defines>
`define CMD_XADD    #AUTOGEN_NEXT_CMD

`define CMDEX_XADD_FIRST        4'd0
`define CMDEX_XADD_LAST         4'd1
</defines>

<decode>
dec_ready_2byte_modregrm && { decoder[7:1], 1'b0 } == 8'hC0
prefix_group_1_lock && `DEC_MODREGRM_IS_MOD_11
`CMD_XADD
IF(decoder[0] == 1'b0); SET(dec_is_8bit); ENDIF();
SET(consume_modregrm_one);
SET(dec_is_complex);
</decode>

<microcode>
`CMDEX_XADD_FIRST
LAST(`CMDEX_XADD_LAST);
</microcode>

<read>
IF(rd_cmd == `CMD_XADD && rd_cmdex == `CMDEX_XADD_FIRST);
    
    SET(rd_src_is_reg);

    // dst: reg, src: reg
    IF(rd_modregrm_mod == 2'b11);
            
        SET(rd_dst_is_rm);
            
        IF(rd_mutex_busy_modregrm_reg || rd_mutex_busy_modregrm_rm); SET(rd_waiting); ENDIF();
    ENDIF();

    // dst: memory, src: reg
    IF(rd_modregrm_mod != 2'b11);
        
        SET(rd_dst_is_memory);
            
        IF(rd_mutex_busy_modregrm_reg || rd_mutex_busy_memory); 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 == `CMD_XADD && rd_cmdex == `CMDEX_XADD_LAST);
    
    SET(rd_dst_is_reg);
    
    SET(rd_req_reg);
    SET(rd_req_eflags);
    
    SET(rd_req_rm,      rd_modregrm_mod == 2'b11);
    SET(rd_req_memory,  rd_modregrm_mod != 2'b11);
ENDIF();
</read>

<execute>
IF(exe_cmd == `CMD_XADD && exe_cmdex == `CMDEX_XADD_FIRST);
    
    SET(exe_arith_index, (`ARITH_VALID | `ARITH_ADD));
    SET(exe_result,  exe_arith_add[31:0]);
    SAVE(exe_buffer, dst);
ENDIF();
</execute>

<execute>
IF(exe_cmd == `CMD_XADD && exe_cmdex == `CMDEX_XADD_LAST);
    
    SET(exe_result, exe_buffer);
ENDIF();
</execute>

<write>
IF(wr_cmd == `CMD_XADD && wr_cmdex == `CMDEX_XADD_FIRST);
    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);
    
    SAVE(zflag, zflag_result);
    SAVE(sflag, sflag_result);
    SAVE(pflag, pflag_result);

    SAVE(aflag, aflag_arith);
    SAVE(cflag, cflag_arith);
    SAVE(oflag, oflag_arith);
    
    SET(wr_not_finished);
ENDIF();  
</write>

<write>
IF(wr_cmd == `CMD_XADD && wr_cmdex == `CMDEX_XADD_LAST);
    IF(wr_modregrm_mod != 2'b11 || wr_modregrm_reg != wr_modregrm_rm);
        SET(write_regrm);
    ENDIF();
ENDIF();
</write>

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