Retro/pcjs
Watch
1
0
Fork
You've already forked pcjs
 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Updated the extended logical operations (LSHC and ROTC) to treat the result as a 71-bit result, and ASHC to treat it as a 70-bit result

Browse source
This commit is contained in:
Jeff 2017-03-06 16:42:29 -08:00 • committed by Jeff Parsons
commit 04ae721eb6
1 changed files with 16 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

16
modules/shared/lib/int36.js
View file

@ -694,6 +694,7 @@ class Int36 {
{ {
num = Int36.validate(num); num = Int36.validate(num);
this.error = Int36.ERROR.NONE; this.error = Int36.ERROR.NONE;
/* /*
* Convert the unsigned 18-bit value in regEA to a signed 8-bit value (+/-255). * Convert the unsigned 18-bit value in regEA to a signed 8-bit value (+/-255).
*/ */
@ -757,6 +758,10 @@ class Int36 {
else { else {
/* /*
* Simulate opASHC() * Simulate opASHC()
*
* TODO: Note that we force the result to be treated as a 70-bit result (we set magnitude to 70 at the end);
* however, what should happen if the incoming value wasn't a proper 70-bit value (ie, if the signs of value
* and extended didn't match)?
*/ */
var bits; var bits;
var wRight = this.value; var wRight = this.value;
@ -879,6 +884,7 @@ class Int36 {
} }
this.value = wRight; this.value = wRight;
this.extended = wLeft; this.extended = wLeft;
this.magnitude = 70;
} }
} }
} }
@ -955,6 +961,11 @@ class Int36 {
} }
this.value = wRight; this.value = wRight;
this.extended = wLeft; this.extended = wLeft;
/*
* TODO: Perhaps we should support magnitude 72 as way of indicating that the value should always be
* treated as an unsigned 72-bit value?
*/
this.magnitude = 71;
} }
} }
} }
@ -1019,6 +1030,11 @@ class Int36 {
} }
this.value = wRight; this.value = wRight;
this.extended = wLeft; this.extended = wLeft;
/*
* TODO: Perhaps we should support magnitude 72 as way of indicating that the value should always be
* treated as an unsigned 72-bit value?
*/
this.magnitude = 71;
} }
} }
} }