Issue #20699: Merge io bytes-like fixes from 3.5

1 files changed, 38 insertions, 0 deletions

diff --git a/Python/wordcode_helpers.h b/Python/wordcode_helpers.h
new file mode 100644
index 0000000000..b61ba33d8f
--- /dev/null
+++ b/Python/wordcode_helpers.h
@@ -0,0 +1,38 @@
+/* This file contains code shared by the compiler and the peephole
+   optimizer.
+ */
+
+/* Minimum number of bytes necessary to encode instruction with EXTENDED_ARGs */
+static int
+instrsize(unsigned int oparg)
+{
+    return oparg <= 0xff ? 2 :
+        oparg <= 0xffff ? 4 :
+        oparg <= 0xffffff ? 6 :
+        8;
+}
+
+/* Spits out op/oparg pair using ilen bytes. codestr should be pointed at the
+   desired location of the first EXTENDED_ARG */
+static void
+write_op_arg(unsigned char *codestr, unsigned char opcode,
+    unsigned int oparg, int ilen)
+{
+    switch (ilen) {
+        case 8:
+            *codestr++ = EXTENDED_ARG;
+            *codestr++ = (oparg >> 24) & 0xff;
+        case 6:
+            *codestr++ = EXTENDED_ARG;
+            *codestr++ = (oparg >> 16) & 0xff;
+        case 4:
+            *codestr++ = EXTENDED_ARG;
+            *codestr++ = (oparg >> 8) & 0xff;
+        case 2:
+            *codestr++ = opcode;
+            *codestr++ = oparg & 0xff;
+            break;
+        default:
+            assert(0);
+    }
+}