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

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<defines>
`define CMD_PUSH        #AUTOGEN_NEXT_CMD

`define CMDEX_PUSH_implicit     4'd0
`define CMDEX_PUSH_immediate_se 4'd1
`define CMDEX_PUSH_immediate    4'd2
`define CMDEX_PUSH_modregrm     4'd3
</defines>

<decode>
dec_ready_one && { decoder[7:3], 3'b0 } == 8'h50
`CMD_PUSH
SET(dec_cmdex, `CMDEX_PUSH_implicit);
SET(consume_one);
</decode>

<decode>
dec_ready_one_imm && (decoder[7:0] == 8'h6A || decoder[7:0] == 8'h68)
`CMD_PUSH
IF(decoder[1]); SET(dec_cmdex, `CMDEX_PUSH_immediate_se); ELSE(); SET(dec_cmdex, `CMDEX_PUSH_immediate); ENDIF();
SET(consume_one_imm);
</decode>

<decode>
dec_ready_modregrm_one && decoder[7:0] == 8'hFF && decoder[13:11] == 3'd6
`CMD_PUSH
SET(dec_cmdex, `CMDEX_PUSH_modregrm);
SET(consume_modregrm_one);
</decode>

<read>
IF(rd_cmd == `CMD_PUSH && (rd_cmdex == `CMDEX_PUSH_immediate || rd_cmdex == `CMDEX_PUSH_immediate_se));
    SET(rd_src_is_imm);

    SET(rd_req_memory);
    SET(rd_req_esp);
ENDIF();
</read>

<read>
IF(rd_cmd == `CMD_PUSH && rd_cmdex == `CMDEX_PUSH_implicit);

    SET(rd_src_is_implicit_reg);

    SET(rd_req_memory);
    SET(rd_req_esp);

    IF(rd_mutex_busy_implicit_reg); SET(rd_waiting); ENDIF();
ENDIF();
</read>

<read>
IF(rd_cmd == `CMD_PUSH && rd_cmdex == `CMDEX_PUSH_modregrm);
    
    SET(rd_req_memory);
    SET(rd_req_esp);

    // dst: reg
    IF(rd_modregrm_mod == 2'b11);
        
        SET(rd_src_is_rm);
        
        IF(rd_mutex_busy_modregrm_rm); SET(rd_waiting); ENDIF();
    ENDIF();

    // dst: memory
    IF(rd_modregrm_mod != 2'b11);
        
        SET(rd_src_is_memory);
    
        IF(rd_mutex_busy_memory); SET(rd_waiting);
        ELSE();
            SET(read_virtual);

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

<execute>
IF(exe_cmd == `CMD_PUSH);
    
    IF(exe_cmdex == `CMDEX_PUSH_immediate_se);
        SET(exe_result_push, { {24{src[7]}}, src[7:0] });
    ELSE();
        SET(exe_result_push, src);
    ENDIF();

    IF(exe_mutex_current[`MUTEX_ESP_BIT]); SET(exe_waiting); ENDIF();
ENDIF();
</execute>

<write>
IF(wr_cmd == `CMD_PUSH);

    SET(wr_push_ss_fault_check);
    SET(wr_one_cycle_wait);
    
    IF(~(write_for_wr_ready)); SET(wr_waiting); ENDIF();
    
    IF(~(wr_push_ss_fault));
        SET(write_stack_virtual);
    ENDIF();
    
    IF(write_for_wr_ready && ~(wr_push_ss_fault));
        SAVE(esp, wr_stack_esp);
    ENDIF();
ENDIF();
</write>

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