[jak2] implement abandon-thread (#2396)

implements `abandon-thread` for when we want to return from a thread,
but are in a `post` thread which normally disallows this.

goal_src/jak2/engine/anim/aligner.gc

@@ -9,8 +9,6 @@
 
 ;; DECOMP BEGINS
 
-;; ERROR: Unsupported inline assembly instruction kind - [lw ra, return-from-thread(s7)]
-;; ERROR: Unsupported inline assembly instruction kind - [jr ra]
 (defmethod compute-alignment! align-control ((obj align-control))
   (local-vars (a0-10 symbol) (s7-0 none) (ra-0 int))
   (rlet ((vf0 :class vf)
@@ -30,11 +28,8 @@
              )
             (else
               (when (!= (-> v1-7 type) art-joint-anim)
-                (break!) ;; modified.
-                ; (go process-drawable-art-error "align joint-anim")
-                ; (.lw ra-0 return-from-thread s7-0)
-                ; (.jr ra-0)
-                ; (nop!)
+                (go process-drawable-art-error "align joint-anim")
+                (abandon-thread)
                 0
                 )
               )

goal_src/jak2/engine/process-drawable/process-drawable.gc

@@ -1203,8 +1203,6 @@
   0
   )
 
-;; ERROR: Unsupported inline assembly instruction kind - [lw ra, return-from-thread(s7)]
-;; ERROR: Unsupported inline assembly instruction kind - [jr ra]
 (defmethod update-anim-data joint-control ((obj joint-control))
   (local-vars (s7-0 none) (ra-0 int))
   (let ((s5-0 (+ (-> obj active-channels) (-> obj float-channels))))
@@ -1217,11 +1215,8 @@
             (let ((s2-0 (-> s3-0 frame-group)))
               (when (not (and s2-0 (nonzero? s2-0) (= (logand (the-as int s2-0) 7) 4) (= (-> s2-0 type) art-joint-anim)))
                 (go process-drawable-art-error "joint-anim")
-                (break!)
-                ;; (.lw ra-0 return-from-thread s7-0)
-                ;; (.jr ra-0)
-                ;; (nop!)
-                ;; 0
+                (abandon-thread)
+                0
                 )
               (when (nonzero? (-> s2-0 frames flags))
                 (cond
@@ -1246,8 +1241,6 @@
   (none)
   )
 
-;; ERROR: Unsupported inline assembly instruction kind - [lw ra, return-from-thread(s7)]
-;; ERROR: Unsupported inline assembly instruction kind - [jr ra]
 (defmethod evaluate-joint-control process-drawable ((obj process-drawable))
   (local-vars (s1-0 joint-control-channel) (s2-0 int) (s4-0 uint) (s7-0 none) (ra-0 int))
   (with-pp
@@ -1287,11 +1280,8 @@
             (let ((s0-0 (-> s1-0 frame-group)))
               (when (not (and s0-0 (nonzero? s0-0) (= (logand (the-as int s0-0) 7) 4) (= (-> s0-0 type) art-joint-anim)))
                 (go process-drawable-art-error "joint-anim")
-                (break!)
-                ;; (.lw ra-0 return-from-thread s7-0)
-                ;; (.jr ra-0)
-                ;; (nop!)
-                ;; 0
+                (abandon-thread)
+                0
                 )
               (when (nonzero? (-> s0-0 frames flags))
                 (cond

goal_src/jak2/kernel/gkernel.gc

@@ -510,6 +510,22 @@
     )
   )
 
+(defmacro abandon-thread ()
+  ;; abandon this one too.
+  ;; NOTE - this is different from GOAL.
+  ;; GOAL installs this as the return address for this function and returns normally.
+  ;; but we don't because I don't have an easy way to find where to stick this.
+  ;; I can't see how this makes a difference, as all non-main threads seem
+  ;; temporary, but if this turns out to be false, we will need to change this.
+  `(rlet ((temp)
+        (off :reg r15 :type uint :reset-here #t))
+    (.mov temp return-from-thread) ;; could probably just call this...
+    (.add temp off)
+    (.push temp)
+    (.ret)
+    )
+  )
+
 (defun reset-and-call ((obj thread) (func function))
   "Make the given thread the top thread, reset the stack, and call the function.
   Sets up a return trampoline so when the function returns it will return to the
@@ -2388,13 +2404,7 @@
         ;; then go back to the kernel dispatcher immediately.
         ((= (-> *kernel-context* current-process) obj)
          (set! (-> obj status) 'dead)
-         (let ((temp (the uint return-from-thread)))
-           (rlet ((off :reg r15 :type uint))
-                 (+! temp off)
-                 (.push temp)
-                 (.ret)
-                 )
-           )
+         (abandon-thread)
          )
         ;; if you deactivated yourself while initializing, we should go back to
         ;; the place where initialize was called in another process, not all the way back to the kernel.

goal_src/jak2/kernel/gstate.gc

@@ -447,14 +447,8 @@ It type checks the arguments for the entry function.
          ;; but we don't because I don't have an easy way to find where to stick this.
          ;; I can't see how this makes a difference, as all non-main threads seem
          ;; temporary, but if this turns out to be false, we will need to change this.
-         (rlet ((temp)
-                (off :reg r15 :type uint :reset-here #t))
-           (.mov temp return-from-thread) ;; could probably just call this...
-           (.add temp off)
-           (.push temp)
-           (.ret)
-           #f ;; can't get here
-           )
+         (abandon-thread)
+         #f ;; can't get here
          )
        )
       )