From 704265bd3c805ea71c0a0bc8a4280de46976b126 Mon Sep 17 00:00:00 2001
From: Kartik Agaram <vc@akkartik.com>
Date: Fri, 27 Nov 2020 12:39:18 -0800
Subject: 7289

---
 406int32.mu | 140 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 140 insertions(+)
 create mode 100644 406int32.mu

(limited to '406int32.mu')

diff --git a/406int32.mu b/406int32.mu
new file mode 100644
index 00000000..4d762678
--- /dev/null
+++ b/406int32.mu
@@ -0,0 +1,140 @@
+# Some slow but convenient helpers
+
+# slow, iterative divide instruction
+# preconditions: _nr >= 0, _dr > 0
+fn try-divide _nr: int, _dr: int -> _/eax: int {
+  # x = next power-of-2 multiple of _dr after _nr
+  var x/ecx: int <- copy 1
+  {
+#?     print-int32-hex 0, x
+#?     print-string 0, "\n"
+    var tmp/edx: int <- copy _dr
+    tmp <- multiply x
+    compare tmp, _nr
+    break-if->
+    x <- shift-left 1
+    loop
+  }
+#?   print-string 0, "--\n"
+  # min, max = x/2, x
+  var max/ecx: int <- copy x
+  var min/edx: int <- copy max
+  min <- shift-right 1
+  # narrow down result between min and max
+  var i/eax: int <- copy min
+  {
+#?     print-int32-hex 0, i
+#?     print-string 0, "\n"
+    var foo/ebx: int <- copy _dr
+    foo <- multiply i
+    compare foo, _nr
+    break-if->
+    i <- increment
+    loop
+  }
+  var result/eax: int <- copy i
+  result <- decrement
+#?   print-string 0, "=> "
+#?   print-int32-hex 0, result
+#?   print-string 0, "\n"
+  return result
+}
+
+fn test-try-divide-1 {
+  var result/eax: int <- try-divide 0, 2
+  check-ints-equal result, 0, "F - try-divide-1"
+}
+
+fn test-try-divide-2 {
+  var result/eax: int <- try-divide 1, 2
+  check-ints-equal result, 0, "F - try-divide-2"
+}
+
+fn test-try-divide-3 {
+  var result/eax: int <- try-divide 2, 2
+  check-ints-equal result, 1, "F - try-divide-3"
+}
+
+fn test-try-divide-4 {
+  var result/eax: int <- try-divide 4, 2
+  check-ints-equal result, 2, "F - try-divide-4"
+}
+
+fn test-try-divide-5 {
+  var result/eax: int <- try-divide 6, 2
+  check-ints-equal result, 3, "F - try-divide-5"
+}
+
+fn test-try-divide-6 {
+  var result/eax: int <- try-divide 9, 3
+  check-ints-equal result, 3, "F - try-divide-6"
+}
+
+fn test-try-divide-7 {
+  var result/eax: int <- try-divide 0xc, 4
+  check-ints-equal result, 3, "F - try-divide-7"
+}
+
+fn test-try-divide-8 {
+  var result/eax: int <- try-divide 0x1b, 3  # 27/3
+  check-ints-equal result, 9, "F - try-divide-8"
+}
+
+fn test-try-divide-9 {
+  var result/eax: int <- try-divide 0x1c, 3  # 28/3
+  check-ints-equal result, 9, "F - try-divide-9"
+}
+
+# only positive dr for now
+fn try-modulo nr: int, dr: int -> _/eax: int {
+  var _positive-nr/eax: int <- abs nr
+  var positive-nr/ecx: int <- copy _positive-nr
+  var result/eax: int <- try-divide positive-nr, dr
+  result <- multiply dr
+  result <- subtract positive-nr
+  result <- negate
+  return result
+}
+
+fn test-try-modulo-negative-nr {
+  var result/eax: int <- try-modulo -0xa, 7
+  check-ints-equal result, 3, "F - test-try-modulo-negative-nr"
+}
+
+# slow, iterative shift-left instruction
+# preconditions: _nr >= 0, _dr > 0
+fn repeated-shift-left nr: int, dr: int -> _/eax: int {
+  var result/eax: int <- copy nr
+  {
+    compare dr, 0
+    break-if-<=
+    result <- shift-left 1
+    decrement dr
+    loop
+  }
+  return result
+}
+
+# slow, iterative shift-right instruction
+# preconditions: _nr >= 0, _dr > 0
+fn repeated-shift-right nr: int, dr: int -> _/eax: int {
+  var result/eax: int <- copy nr
+  {
+    compare dr, 0
+    break-if-<=
+    result <- shift-right 1
+    decrement dr
+    loop
+  }
+  return result
+}
+
+fn abs n: int -> _/eax: int {
+  var result/eax: int <- copy n
+  {
+    compare n, 0
+    break-if->=
+    result <- negate
+  }
+  return result
+}
-- 
cgit 1.4.1-2-gfad0