From 341682f474c42f8cde8be5c8b80df4b58d31f7b9 Mon Sep 17 00:00:00 2001
From: Danny Milosavljevic <dannym@scratchpost.org>
Date: Tue, 16 Jun 2020 14:08:58 +0200
Subject: [PATCH] ARM: Avoid using (abs INT_MIN) and (- INT_MIN).

* module/mescc/armv4/as.scm (immediate->r0): Inline abs.
(armv4:value->r): Inline abs.
(armv4:local->r): Inline abs.
(armv4:r->local+n): Inline abs.
(armv4:r-byte-mem-add): Inline abs.
(armv4:r-word-mem-add): Inline abs.
(armv4:local-ptr->r): Inline abs.
(armv4:r+value): Inline abs.
(armv4:r-cmp-value): Inline abs.
(armv4:r0+value): Inline abs.
(armv4:byte-r->local+n): Inline abs.
(armv4:word-r->local+n): Inline abs.
---
 module/mescc/armv4/as.scm | 131 +++++++++++++++++++++++---------------
 1 file changed, 78 insertions(+), 53 deletions(-)

diff --git a/module/mescc/armv4/as.scm b/module/mescc/armv4/as.scm
index 3fb97bbc..8b53c30b 100644
--- a/module/mescc/armv4/as.scm
+++ b/module/mescc/armv4/as.scm
@@ -47,19 +47,23 @@
     `(,`(,(string-append "mov____%" r ",0x32(%ebp)") (#:immediate ,n)))))
 
 (define (immediate->r0 v)
-  (if (< (abs v) #x100)
-      (if (< v 0)
+  (if (< v 0)
+      (if (> v #x-100)
          `(((#:immediate1 ,(- -1 v)) "mvn____%r0,$i8"))
-         `(((#:immediate1 ,v) "mov____$i8,%r0")))
-     `(("mov____$i32,%r0" (#:immediate ,v)))))
+         `(("mov____$i32,%r0" (#:immediate ,v))))
+      (if (< v #x100)
+         `(((#:immediate1 ,v) "mov____$i8,%r0"))
+         `(("mov____$i32,%r0" (#:immediate ,v))))))
 
 (define (armv4:value->r info v)
   (let ((r (get-r info)))
-    (if (< (abs v) #x100)
-        (if (< v 0)
+    (if (< v 0)
+        (if (> v #x-100)
            `(((#:immediate1 ,(- -1 v)) ,(string-append "mvn____%" r ",$i8")))
-           `(((#:immediate1 ,v) ,(string-append "mov____$i8,%" r))))
-        `((,(string-append "mov____$i32,%" r) (#:immediate ,v))))))
+           `((,(string-append "mov____$i32,%" r) (#:immediate ,v))))
+        (if (< v #x100)
+           `(((#:immediate1 ,v) ,(string-append "mov____$i8,%" r)))
+           `((,(string-append "mov____$i32,%" r) (#:immediate ,v)))))))
 
 (define (armv4:ret . rest)
   "Note: Pretends to be on x86 a lot"
@@ -74,13 +78,15 @@
 (define (armv4:local->r info n)
   (let ((r (get-r info))
         (n (- 0 (* 4 n))))
-    (if (< (abs n) #x100)
-        (if (< n 0)
-           `(((#:immediate1 ,(abs n))
+    (if (< n 0)
+        (if (> n #x-100)
+           `(((#:immediate1 ,(- n))
               ,(string-append "ldr____%" r ",(%fp,-#$i8)")))
+           `((,(string-append "mov____0x32(%ebp),%" r) (#:immediate ,n))))
+        (if (< n #x100)
            `(((#:immediate1 ,n)
-              ,(string-append "ldr____%" r ",(%fp,+#$i8)"))))
-        `((,(string-append "mov____0x32(%ebp),%" r) (#:immediate ,n))))))
+              ,(string-append "ldr____%" r ",(%fp,+#$i8)")))
+           `((,(string-append "mov____0x32(%ebp),%" r) (#:immediate ,n)))))))
 
 (define (armv4:r0+r1 info)
   (let ((r0 (get-r0 info))
@@ -122,13 +128,17 @@
 (define (armv4:r->local+n info id n)
   (let ((n (+ (- 0 (* 4 id)) n))
         (r (get-r info)))
-    `(,(if (< (abs n) #x100)
-           (if (< n 0)
-              `((#:immediate1 ,(abs n))
-                ,(string-append "str____%" r ",(%fp,-#$i8)"))
-              `((#:immediate1 ,n)
-                ,(string-append "str____%" r ",(%fp,+#$i8)")))
-           `(,(string-append "mov____%" r ",0x32(%ebp)") (#:immediate ,n))))))
+    (if (< n 0)
+        (if (> n #x-100)
+           `(((#:immediate1 ,(- n))
+              ,(string-append "str____%" r ",(%fp,-#$i8)")))
+           `((,(string-append "mov____%" r ",0x32(%ebp)")
+             (#:immediate ,n))))
+        (if (< n #x100)
+           `(((#:immediate1 ,n)
+              ,(string-append "str____%" r ",(%fp,+#$i8)")))
+           `((,(string-append "mov____%" r ",0x32(%ebp)")
+              (#:immediate ,n)))))))
 
 (define (armv4:r-mem-add info v)
   (let ((r (get-r info)))
@@ -139,7 +149,7 @@
     `((,(string-append "push___%r0"))
       (,(string-append "ldrb___%r0,(%" r ")"))
       ,(if (< v 0)
-          `((#:immediate1 ,(abs v)) ,(string-append "sub____$i8,%r0"))
+          `((#:immediate1 ,(- v)) ,(string-append "sub____$i8,%r0"))
           `((#:immediate1 ,v) ,(string-append "add____$i8,%r0")))
       (,(string-append "strb___%r0,(%" r ")"))
       (,(string-append "pop____%r0")))))
@@ -149,7 +159,7 @@
     `((,(string-append "push___%r0"))
       (,(string-append "ldrh___%r0,(%" r ")"))
       ,(if (< v 0)
-          `((#:immediate1 ,(abs v)) ,(string-append "sub____$i8,%r0"))
+          `((#:immediate1 ,(- v)) ,(string-append "sub____$i8,%r0"))
           `((#:immediate1 ,v) ,(string-append "add____$i8,%r0")))
       (,(string-append "strh___%r0,(%" r ")"))
       (,(string-append "pop____%r0")))))
@@ -158,11 +168,13 @@
   (let ((r (get-r info)))
     (let ((n (- 0 (* 4 n))))
       `((,(string-append "mov____%ebp,%" r))
-        ,(if (< (abs n) #x100)
-            (if (< n 0)
-               `((#:immediate1 ,(abs n)) ,(string-append "sub____$i8,%" r))
-               `((#:immediate1 ,n) ,(string-append "add____$i8,%" r)))
-            `(,(string-append "add____$i32,%" r) (#:immediate ,n)))))))
+        ,(if (< n 0)
+            (if (> n #x-100)
+               `((#:immediate1 ,(- n)) ,(string-append "sub____$i8,%" r))
+               `(,(string-append "add____$i32,%" r) (#:immediate ,n)))
+            (if (< n #x100)
+               `((#:immediate1 ,n) ,(string-append "add____$i8,%" r))
+               `(,(string-append "add____$i32,%" r) (#:immediate ,n))))))))
 
 (define (armv4:label->r info label)
   (let ((r (get-r info)))
@@ -381,11 +393,13 @@
 
 (define (armv4:r+value info v)
   (let ((r (get-r info)))
-    (if (< (abs v) #x100)
-       (if (< v 0)
-          `(((#:immediate1 ,(abs v)) ,(string-append "sub____$i8,%" r)))
-          `(((#:immediate1 ,v) ,(string-append "add____$i8,%" r))))
-       `((,(string-append "add____$i32,%" r) (#:immediate ,v))))))
+    (if (< v 0)
+        (if (> v #x-100)
+           `(((#:immediate1 ,(- v)) ,(string-append "sub____$i8,%" r)))
+           `((,(string-append "add____$i32,%" r) (#:immediate ,v))))
+        (if (< v #x100)
+           `(((#:immediate1 ,v) ,(string-append "add____$i8,%" r)))
+           `((,(string-append "add____$i32,%" r) (#:immediate ,v)))))))
 
 (define (armv4:r0->r1-mem info)
   (let ((r0 (get-r0 info))
@@ -404,11 +418,13 @@
 
 (define (armv4:r-cmp-value info v)
   (let ((r (get-r info)))
-    (if (< (abs v) #x100)
-        (if (< v 0)
-           `(((#:immediate1 ,(abs v)) ,(string-append "cmn____$i8,%" r)))
-           `(((#:immediate1 ,v) ,(string-append "cmp____$i8,%" r))))
-       `((,(string-append "cmp____$i32,%" r) (#:immediate ,v))))))
+    (if (< v 0)
+        (if (> v #x-100)
+            `(((#:immediate1 ,(- v)) ,(string-append "cmn____$i8,%" r)))
+            `((,(string-append "cmp____$i32,%" r) (#:immediate ,v))))
+        (if (< v #x100)
+           `(((#:immediate1 ,v) ,(string-append "cmp____$i8,%" r)))
+           `((,(string-append "cmp____$i32,%" r) (#:immediate ,v)))))))
 
 (define (armv4:push-register info r)
   `((,(string-append "push___%" r))))
@@ -469,11 +485,13 @@
 
 (define (armv4:r0+value info v)
   (let ((r0 (get-r0 info)))
-    (if (< (abs v) #x100)
-        (if (< v 0)
-           `(((#:immediate1 ,(abs v)) ,(string-append "sub____$i8,%" r0)))
+    (if (< v 0)
+        (if (> v #x-100)
+           `(((#:immediate1 ,(- v)) ,(string-append "sub____$i8,%" r0)))
+           `((,(string-append "add____$i32,%" r0) (#:immediate ,v))))
+        (if (< v #x100)
            `(((#:immediate1 ,v) ,(string-append "add____$i8,%" r0))))
-       `((,(string-append "add____$i32,%" r0) (#:immediate ,v))))))
+           `((,(string-append "add____$i32,%" r0) (#:immediate ,v))))))
 
 (define (armv4:value->r0 info v)
   (let ((r0 (get-r0 info)))
@@ -482,24 +500,31 @@
 (define (armv4:byte-r->local+n info id n)
   (let* ((n (+ (- 0 (* 4 id)) n))
          (r (get-r info)))
-    `(,(if (< (abs n) #x100)
-           (if (< n 0)
-               `((#:immediate1 ,(abs n))
-                 ,(string-append "strb___%" r ",(%fp,-#$i8)"))
-               `((#:immediate1 ,n)
-                 ,(string-append "strb___%" r ",(%fp,+#$i8)")))
-           `(,(string-append "strb___%" r ",0x32(%ebp)") (#:immediate ,n))))))
+    `(,(if (< n 0)
+           (if (> n #x-100)
+              `((#:immediate1 ,(- n))
+                ,(string-append "strb___%" r ",(%fp,-#$i8)"))
+              `(,(string-append "strb___%" r ",0x32(%ebp)")
+                (#:immediate ,n)))
+           (if (< n #x100)
+              `((#:immediate1 ,n)
+                ,(string-append "strb___%" r ",(%fp,+#$i8)"))
+              `(,(string-append "strb___%" r ",0x32(%ebp)") (#:immediate ,n)))))))
 
 (define (armv4:word-r->local+n info id n)
   (let* ((n (+ (- 0 (* 4 id)) n))
          (r (get-r info)))
-    `(,(if (< (abs n) #x100)
-           (if (< n 0)
-               `((#:immediate1 ,(abs n))
+    `(,(if (< n 0)
+           (if (> n #x-100)
+               `((#:immediate1 ,(- n))
                  ,(string-append "strh___%" r ",(%fp,-#$i8)"))
+               `(,(string-append "strh___%" r ",0x32(%ebp)")
+                 (#:immediate ,n)))
+           (if (< n #x100)
                `((#:immediate1 ,n)
-                 ,(string-append "strh___%" r ",(%fp,+#$i8)")))
-           `(,(string-append "strh___%" r ",0x32(%ebp)") (#:immediate ,n))))))
+                 ,(string-append "strh___%" r ",(%fp,+#$i8)"))
+               `(,(string-append "strh___%" r ",0x32(%ebp)")
+                 (#:immediate ,n)))))))
 
 (define (armv4:r-and info v)
   (let ((r (get-r info)))