about rdword

caskaz

Hi.
I solved sine-wave by gived advise.
But I have one more question.

I use sin_table_end($F001) to get data for [noparse][[/noparse]90 - 179.95] and [noparse][[/noparse]270 - 359.95]degree.
But it also fine works for $F000).

I checked by using PASM
For example
sin_table($E000)
[noparse][[/noparse]0 - 89.95] $E002 --> $32
$E004 --> $65

sin_table_end($F001)
[noparse][[/noparse]90 - 179.95] $E003 --> $32
$E005 --> $65

Instruction "rdword" is automatically search top addres(even) of word data?

pullmoll

caskaz said...
Instruction "rdword" is automatically search top addres(even) of word data?

Yes. I stumbled across this today in my own code. The manual says the address' lower bit will be cleared to zero resulting in an address pointing to a word boundary and this means you can load words from addresses divisible by two only. I don't know if perhaps you have to use $f002. The manual's examples say $f001...

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potatohead

It was my understanding that strict alignment is in play for all the data length types. long = 00, word = 0, byte is just byte.

Just do [noparse][[/noparse]address] & %00, or %0 to get the effective address for a given fetch from the HUB, and that's how it will work. $F001 will just be $F000. $F002 will be $F002, for words.

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MagIO2

I did not find code in the manual (V1.1) that accessed $F001. It only says that the sine-table is stored from $E000 to $F001. $E000-$EFFF are 2048 words and $F000/$F001 are the 2049th word. Of course the code which calculates the address will end up in $F000 to fetch the last word.

pullmoll

MagIO2 said...
I did not find code in the manual (V1.1) that accessed $F001. It only says that the sine-table is stored from $E000 to $F001. $E000-$EFFF are 2048 words and $F000/$F001 are the 2049th word. Of course the code which calculates the address will end up in $F000 to fetch the last word.

Yes, it's my bad. I gave the OP a hint from the top of my head, without looking into the manual again. Of course $f001 is used, but it's just the MSB of the word at $f000. D'OH!

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
He died at the console of hunger and thirst.
Next day he was buried. Face down, nine edge first.