Implementation starting to a look a bit hairy already
The boring part related to reading and writing should be mostly done now.
![export function read(addr: number) {
let data
if (addr < 0 || addr >= MEM_SIZE - 1) {
if (addr === MEM_SIZE - 1) {
data = (mem[addr] << 8) + mem[0]
} else {
error(`read: invalid address ${addr}`)
}
} else {
data = (mem[addr] << 8) + mem[addr + 1]
}
if ((data & 0x8000) > 0) {
return data - 0x10000
} else {
return data
}
}](https://cdn.bsky.app/img/feed_fullsize/plain/did:plc:ih3rt6r3sesh2flndp7oefwc/bafkreicduxehp4izsptpnzg77rjjj22vaipanocinqude2qzufylptt7iq@jpeg)
![export function write(addr: number, num: number) {
if (num < -32768 || num > 32767) {
// Alternatively, we might just do `& 0xffff` and be done with it
error(`write: number doesn't fit ${num}`)
}
let hi = (num & 0xff00) >> 8
let lo = num & 0x00ff
if (addr < 0 || addr >= MEM_SIZE - 1) {
if (addr === MEM_SIZE - 1) {
mem[addr] = hi
mem[0] = lo
} else {
error(`write: invalid address ${addr}`)
}
}
mem[addr] = hi
mem[addr + 1] = lo
}](https://cdn.bsky.app/img/feed_fullsize/plain/did:plc:ih3rt6r3sesh2flndp7oefwc/bafkreid2l4oewhztdlqymwanht77wfjj5fu6ou6e22czuuzultakh2hb5a@jpeg)
