From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Ling Su" To: "Ling Su" , "Nick Garnett" Cc: Subject: Re: [ECOS] Porting eCos to DDB-VRC4375(Memory mapping) Date: Tue, 30 Jan 2001 12:01:00 -0000 Message-id: <015101c08af7$604454e0$0201a8c0@raccoon> References: <000b01c08a63$06a81cd0$0201a8c0@raccoon> <014501c08af4$ce8e27d0$0201a8c0@raccoon> X-SW-Source: 2001-01/msg00480.html Sorry, I checked out the newest CVS version, I found it is correct. So following question is invalid. :) Rgds, -Ling ----- Original Message ----- From: "Ling Su" To: "Nick Garnett" Cc: Sent: Tuesday, January 30, 2001 11:42 AM Subject: Re: [ECOS] Porting eCos to DDB-VRC4375(Memory mapping) > Dear Nick, > > Thanks a lot for you helpful explaination! I found it is not consistent for > the mlt_mips_vr4300_vrc4373_rom.ldi, mlt_mips_vr4300_vrc4373_rom.mlt, and > mlt_mips_vr4300_vrc4373_rom.h. Supposely the *.ldi and *.h are both > generated by *.mlt, right? but in in mlt_mips_vr4300_vrc4373_rom.ldi and > mlt_mips_vr4300_vrc4373_rom.h, we can find the ram ORIGIN is 0x80000200 > LENGTH is 0x7fe00. Any particular reason for this? I am a little bit > confused. > > Regards, > -Ling > > > > > > <2>. In the mlt_mips_vr4300_vrc4373_rom.ldi, > > MEMORY > > { > > ram: ORIGIN = 0x80000800, LENGTH = 0x7F800 > > rom: ORIGIN = 0xBFC0000, LENGTH = 0x80000 > > } > > I don't quite understand the ram LENGTH setting, why we just use 512KB ram > > in rom start up setting? Can we set the ram LENGTH to larger. Another > thing > > is why its ORIGIN is 0x80000800? > > Again, the RAM length is probably just left over from an earlier > version of the code. Generally we use the ROMRAM startup for all > VRC4373 non-RAM configurations, I suspect that the ROM startup has not > been used for a long time and has not been kept up to date. > > The RAM starts at 0x80000800 because we have various tables defined to > go into low RAM. Below 0x80000400 there are hardware defined interrupt > vectors. We have the VSR table at 0x80000400 and the vector table at > 0x80000600. > > > >