About the uclinux starter and memory allocation

dear all,

when i do uclinux according to hippo, now i can run uclinux in my target board(nios2,FLASH8MB(0X000000-0X7FFFFF),SDRAM(8MB)0X800000-0XFFFFFF),but i still don't understand where the zImage file download to,and how does the uclinux work and how does the memory space use?

in my target board:

0x000000|------------------|

------------| ----------------- |

------------|8MB FLASH ---- |

0x7FFFFF |-------------------|

0x800000|-------------------|

-----------|8MB SDRAM ----|

0xd00000|-------------------| <-----kernal config 0x500000+0x800000,why ??

------------|--------------------|

0x0FFFFFF|-------------------|

0x1000000|-- NIOS II ------|

0x10007FF |------------------|

----

IN THE SYSTEM THE RESET ADDRESS 0X000000,EXECPTION ADDRESS 0X800020

COULD YOU TELL ME HOW DOES THE UCLINUX WORK WHEN THE SYSTEM POWER ON?