xlar54 wrote:
Can you tell us more about this 65816 in a vic-20?
What I am attempting is to give the VIC 20 the power of the 65C816. I started by adding logic to put RAM under the kernal and basic roms, plus two 4K blocks of RAM under the character rom. This is all controlled by a register that I mapped to $9200. This was done by further decoding from $9000 with a 2 - 4 decoder. This shadow memory has been tested using a modified assembler for the C64 and runs from RAM under the kernal and basic. Now I'm trying to get the 65C816 to do this also. I am using a 128K static ram chip for now and plan to increase that once the '816 can perform the same test. I'm using Xilinx XC9572's, the 5v version.
When it is all up to snuff, I will need a machine language monitor. I am looking at JamaicaMon, but it has code for the SuperCPU that references bank 1. I don't know anything about the ROMs in the SuperCPU, so I don't know what this code references
Code:
; ** INITIALIZATION **
SUPER CLC
XCE`;NATIVE MODE
REP #$30`;EVERYONE 16-BITS
PER VBREAK
SEI
PLA
STA BKVEC
PER BREAK
PLA
STA $01FC9D`;NBRK
STA $017C9D
LDA #0000
DFB $5B`;DP -> ZERO-PAGE
SEP #$30`;EVERYONE 8-BITS
STA $01FC9F`;BANK 0
STA $017C9F
CLI
LDA #$80
JSR SETMSG
SEC
XCE
JSR INIT`;INIT PPP
BRK
Since my project doesn't have all the special features of the SuperCPU, I'm trying to find out what I need to keep and what can go. I do have WinVICE for the SuperCPU, but know nothing about the roms locations.
Thanks for any help anyone can offer.