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

Added preliminary PDP-10 opcode decoding

Browse source
This commit is contained in:
Jeff Parsons 2017-02-26 09:13:16 -08:00 • committed by Jeff Parsons
commit e3ab5b1ed5
4 changed files with 1302 additions and 904 deletions
Download patch file Download diff file Expand all files Collapse all files

11
modules/pdp10/lib/defines.js
View file

@ -97,6 +97,7 @@ var PDP10 = {
*/
ADDR_INVALID: -1,
ADDR_LIMIT: Math.pow(2, 18),
ADDR_MASK: Math.pow(2, 18) - 1,
DATA_INVALID: -1,
DATA_LIMIT: Math.pow(2, 36),
@ -128,10 +129,10 @@ var PDP10 = {
* 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
* 1 1 1 D D D D D D D O O O I X X X X Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y
*
* Bits 0-22 (I,X,Y) contain what we call a "reference address" (R), which is used to
* calculate the "effective address" (E). To determine E from R, we must extract I, X,
* and Y from R, set E to Y, then add [X] to E if X is non-zero. If I is zero, then
* we're done; otherwise, we must set set R to [E] and repeat the process.
* Bits 0-22 (I,X,Y) contain what we call a "reference address" (R), which is used to calculate the
* "effective address" (E). To determine E from R, we must extract I, X, and Y from R, set E to Y,
* then add [X] to E if X is non-zero. If I is zero, then we're done; otherwise, we must set R to [E]
* and repeat the process.
*/
OPCODE: {
OPMASK: 0o77700, // operation mask
@ -145,8 +146,6 @@ var PDP10 = {
FNMASK: 0o17, // accumulator/function mask (after shift)
IOSHIFT: Math.pow(2, 26), // input-output device code shift
IOMASK: 0o177, // input-output device code mask (after shift)
O_SHIFT: Math.pow(2, 27), // operation shift
O_MASK: 0o777, // operation mask (after shift)
I_BIT: 0o20000000, // indirect bit
X_SHIFT: 18, // X shift
X_MASK: 0o17, // X mask (after shift)