From 3e31560e7df7b07578366da7df58a8598271b482 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=A1szl=C3=B3=20Moln=C3=A1r?=
 <ezerotven+github@gmail.com>
Date: Thu, 13 Apr 2006 12:23:42 +0000
Subject: [PATCH] added a new filter for ARM 24-bit naive calltrick

committer: ml1050 <ml1050> 1144931022 +0000
---
 src/filter/ct.h | 40 ++++++++++++++++++++++++++++++++++++++++
 src/filteri.cpp |  3 +++
 2 files changed, 43 insertions(+)

diff --git a/src/filter/ct.h b/src/filter/ct.h
index 46d0bbec..53dbe4b7 100644
--- a/src/filter/ct.h
+++ b/src/filter/ct.h
@@ -383,6 +383,46 @@ static int s_ct32_e8e9_bswap_be(Filter *f)
 
 #undef CT32
 
+/*************************************************************************
+// 24-bit ARM calltrick ("naive")
+**************************************************************************/
+
+#define CT24ARM(f, cond, addvalue, get, set) \
+    upx_byte *b = f->buf; \
+    upx_byte *b_end = b + f->buf_len - 4; \
+    do { \
+        if (cond) \
+        { \
+            unsigned a = (unsigned) (b - f->buf); \
+            f->lastcall = a; \
+            set(b, get(b) + (addvalue)); \
+            f->calls++; \
+        } \
+        b += 4; \
+    } while (b < b_end); \
+    if (f->lastcall) f->lastcall += 4; \
+    return 0;
+
+
+#define ARMCT_COND (((b[3] & 0x0f) == 0x0b))
+
+static int f_ct24arm_le(Filter *f)
+{
+    CT24ARM(f, ARMCT_COND, a / 4 + f->addvalue, get_le24, set_le24)
+}
+
+static int u_ct24arm_le(Filter *f)
+{
+    CT24ARM(f, ARMCT_COND, 0 - a / 4 - f->addvalue, get_le24, set_le24)
+}
+
+static int s_ct24arm_le(Filter *f)
+{
+    CT24ARM(f, ARMCT_COND, a + f->addvalue, get_le24, set_dummy)
+}
+
+#undef CT24ARM
+#undef ARMCT_COND
 
 /*
 vi:ts=4:et:nowrap
diff --git a/src/filteri.cpp b/src/filteri.cpp
index 10d19ff3..516f993c 100644
--- a/src/filteri.cpp
+++ b/src/filteri.cpp
@@ -224,6 +224,9 @@ const FilterImp::FilterEntry FilterImp::filters[] = {
     { 0x46, 6, 0x00ffffff, f_ctok32_e8e9_bswap_le, u_ctok32_e8e9_bswap_le, s_ctok32_e8e9_bswap_le },
     { 0x49, 6, 0x00ffffff, f_ctok32_e8e9_bswap_le, u_ctok32_e8e9_bswap_le, s_ctok32_e8e9_bswap_le },
 
+    // 24-bit calltrick for arm
+    { 0x50, 8, 0x01ffffff, f_ct24arm_le, u_ct24arm_le, s_ct24arm_le },
+
     // 32-bit cto calltrick with jmp and jcc(swap 0x0f/0x8Y) and relative renumbering
     { 0x80, 8, 0x00ffffff, f_ctojr32_e8e9_bswap_le, u_ctojr32_e8e9_bswap_le, s_ctojr32_e8e9_bswap_le },
     { 0x81, 8, 0x00ffffff, f_ctojr32_e8e9_bswap_le, u_ctojr32_e8e9_bswap_le, s_ctojr32_e8e9_bswap_le },