diff --git a/README.md b/README.md
index 7b3cc97..5b0fd9b 100644
--- a/README.md
+++ b/README.md
@@ -148,6 +148,13 @@ are appreciated. They really are, because they do keep me motivated to continue
 
 ## Changelog
 
+### V0.7 (unreleased)
+
+- Bugfix: `btst` with pc-relative and weird immediate mode was missing (courtesy of Yann).
+- Bugfix: `movem` with pc-relative mode was missing for weird immediate mode (courtesy of Yann).
+- Bugfix: Special registers for address mode matching only worked with lower case register names (courtesy of Yann).
+- Enhancement: Assembler syntax with implicit immediate 1 for shifts and rotations no longer cause syntax errors (courtesy of Yann).
+
 ### V0.6 (09-Aug-21)
 
 - Enhancement: `opt` and several other directives (`printt`, `fail` etc.) no longer causes a syntax error when unquoted.
diff --git a/build.gradle b/build.gradle
index fca299f..4f31f89 100644
--- a/build.gradle
+++ b/build.gradle
@@ -7,7 +7,7 @@ plugins {
 }
 
 group = 'de.platon42'
-version = '0.6'
+version = '0.7'
 sourceCompatibility = "1.8"
 targetCompatibility = "1.8"
 
@@ -57,6 +57,13 @@ runPluginVerifier {
 
 patchPluginXml {
     setChangeNotes("""
+  <h4>V0.7 (unreleased)</h4>
+    <ul>
+      <li>Bugfix: 'btst' with pc-relative and weird immediate mode was missing (courtesy of Yann).
+      <li>Bugfix: 'movem' with pc-relative mode was missing for weird immediate mode (courtesy of Yann).
+      <li>Bugfix: Special registers for address mode matching only worked with lower case register names (courtesy of Yann).
+      <li>Enhancement: Assembler syntax with implicit immediate 1 for shifts and rotations no longer cause syntax errors (courtesy of Yann).
+    </ul>
   <h4>V0.6 (09-Aug-21)</h4>
     <ul>
       <li>Enhancement: 'opt' and several other directives ('printt', 'fail' etc.) no longer causes a syntax error when unquoted.
@@ -71,7 +78,7 @@ patchPluginXml {
     <ul>
       <li>Bugfix: movem ISA was wrong regarding movem.w &lt;ea&gt;,&lt;registerlist&gt; (sign extends registers).
       <li>Cosmetics: Changed Register Flow Documentation wording from 'reads' to 'uses' and from 'modifies' to 'changes'.
-      <li>Bugfix: Minor fix for `andi/eori/ori to ccr` which were not byte sized in ISA.
+      <li>Bugfix: Minor fix for 'andi/eori/ori to ccr' which were not byte sized in ISA.
       <li>Bugfix: Added alternate condition code tests HS (=CC) and LO (=CS).
       <li>Performance: Optimized mnemonic lookup.
       <li>Enhancement: Reworked Instruction Documentation provider, now shows condition codes.
@@ -79,19 +86,6 @@ patchPluginXml {
       <li>New: Added inspection to find dead writes to registers!
       <li>New: Added inspection to warn about unexpected condition code unaffecting instructions before conditional instructions.
     </ul>
-  <h4>V0.4 (03-Aug-21)</h4>
-    <ul>
-      <li>Notice: Due to major new API use, this plugin no longer works on IDEs &gt;=2019.3.1, but rather requires &gt;=2020.3.
-      <li>Enhancement: Added Structure View filters.
-      <li>New: Added inspection to validate the correctness of a MC68000 instruction regarding operation size and address modes.
-      <li>Bugfix: Added several missing assembler directives (opt, machine, etc.).
-      <li>Bugfix: Uppercase hexadecimal literals were not parsed (JFlex bug?).
-      <li>Bugfix: Interpretation of register lists was wrong in BNF.
-      <li>New: Added Documentation Provider for symbol definitions (shows assigned declaration).
-      <li>New: Added Documentation Provider for mnemonics (simple version, generated out of ISA information).
-      <li>Bugfix: Macro definitions with colons and without space supported (as found in P61a source).
-      <li>New: When asking for documentation on registers, a code flow analysis is done. Cool stuff!
-    </ul>
   <p>Full changelog available at <a href="https://github.com/chrisly42/mc68000-asm-plugin#changelog">Github project site</a>.</p>
 """)
 }
diff --git a/src/main/java/de/platon42/intellij/plugins/m68k/asm/M68kIsa.kt b/src/main/java/de/platon42/intellij/plugins/m68k/asm/M68kIsa.kt
index ced94df..aeeced7 100644
--- a/src/main/java/de/platon42/intellij/plugins/m68k/asm/M68kIsa.kt
+++ b/src/main/java/de/platon42/intellij/plugins/m68k/asm/M68kIsa.kt
@@ -44,7 +44,7 @@ enum class AddressMode(val description: String, val syntax: String) {
     PROGRAM_COUNTER_INDIRECT_WITH_DISPLACEMENT("program counter indirect with displacement", "(d16,PC)"),
     ADDRESS_REGISTER_INDIRECT_WITH_INDEX("address register indirect with index", "(d8,An,Xn)"),
     PROGRAM_COUNTER_INDIRECT_WITH_INDEX("program counter indirect with index", "(d8,PC,Xn)"),
-    SPECIAL_REGISTER_DIRECT("special register", "ccr|usp|vbr"),
+    SPECIAL_REGISTER_DIRECT("special register", "sr|ccr|usp|vbr"),
     REGISTER_LIST("register list", "list"),
     IMMEDIATE_DATA("immediate", "#<xxx>"),
     ABSOLUTE_ADDRESS("absolute short/long", "(xxx).w|l")
@@ -202,6 +202,18 @@ object M68kIsa {
         AddressMode.PROGRAM_COUNTER_INDIRECT_WITH_INDEX,
     )
 
+    private val ALL_EXCEPT_AREG_AND_DREG = setOf(
+        AddressMode.ADDRESS_REGISTER_INDIRECT,
+        AddressMode.ADDRESS_REGISTER_INDIRECT_POST_INC,
+        AddressMode.ADDRESS_REGISTER_INDIRECT_PRE_DEC,
+        AddressMode.ADDRESS_REGISTER_INDIRECT_WITH_DISPLACEMENT,
+        AddressMode.ADDRESS_REGISTER_INDIRECT_WITH_INDEX,
+        AddressMode.ABSOLUTE_ADDRESS,
+        AddressMode.IMMEDIATE_DATA,
+        AddressMode.PROGRAM_COUNTER_INDIRECT_WITH_DISPLACEMENT,
+        AddressMode.PROGRAM_COUNTER_INDIRECT_WITH_INDEX,
+    )
+
     private val INDIRECT_MODES = setOf(
         AddressMode.ADDRESS_REGISTER_INDIRECT,
         AddressMode.ADDRESS_REGISTER_INDIRECT_POST_INC,
@@ -256,33 +268,39 @@ object M68kIsa {
     private val ASD_LSD_MODES = listOf(
         AllowedAdrMode(DREG_ONLY, DREG_ONLY, modInfo = RWM_READ_OP1_OPSIZE or RWM_MODIFY_OP2_OPSIZE, affectedCc = cc("*****")),
         AllowedAdrMode(setOf(AddressMode.IMMEDIATE_DATA), DREG_ONLY, modInfo = RWM_MODIFY_OP2_OPSIZE, affectedCc = cc("*****")),
-        AllowedAdrMode(INDIRECT_MODES, null, modInfo = RWM_MODIFY_OP1_OPSIZE, affectedCc = cc("*****")),
+        AllowedAdrMode(INDIRECT_MODES, null, size = OP_SIZE_W, modInfo = RWM_MODIFY_OP1_OPSIZE, affectedCc = cc("*****")),
+        // not an official address mode, but supported by assembler (implicit #1)
+        AllowedAdrMode(DREG_ONLY, null, modInfo = RWM_MODIFY_OP1_OPSIZE, affectedCc = cc("*****"))
     )
 
     private val ROD_MODES = listOf(
         AllowedAdrMode(DREG_ONLY, DREG_ONLY, modInfo = RWM_READ_OP1_OPSIZE or RWM_MODIFY_OP2_OPSIZE, affectedCc = cc("-**0*")),
         AllowedAdrMode(setOf(AddressMode.IMMEDIATE_DATA), DREG_ONLY, modInfo = RWM_MODIFY_OP2_OPSIZE, affectedCc = cc("-**0*")),
-        AllowedAdrMode(INDIRECT_MODES, null, modInfo = RWM_MODIFY_OP1_OPSIZE, affectedCc = cc("-**0*")),
+        AllowedAdrMode(INDIRECT_MODES, null, size = OP_SIZE_W, modInfo = RWM_MODIFY_OP1_OPSIZE, affectedCc = cc("-**0*")),
+        // not an official address mode, but supported by assembler (implicit #1)
+        AllowedAdrMode(DREG_ONLY, null, modInfo = RWM_MODIFY_OP1_OPSIZE, affectedCc = cc("-**0*")),
     )
 
     private val ROXD_MODES = listOf(
         AllowedAdrMode(DREG_ONLY, DREG_ONLY, modInfo = RWM_READ_OP1_OPSIZE or RWM_MODIFY_OP2_OPSIZE, affectedCc = cc("***0*"), testedCc = cc("?----")),
         AllowedAdrMode(setOf(AddressMode.IMMEDIATE_DATA), DREG_ONLY, modInfo = RWM_MODIFY_OP2_OPSIZE, affectedCc = cc("***0*"), testedCc = cc("?----")),
-        AllowedAdrMode(INDIRECT_MODES, null, modInfo = RWM_MODIFY_OP1_OPSIZE, affectedCc = cc("***0*"), testedCc = cc("?----")),
+        AllowedAdrMode(INDIRECT_MODES, null, size = OP_SIZE_W, modInfo = RWM_MODIFY_OP1_OPSIZE, affectedCc = cc("***0*"), testedCc = cc("?----")),
+        // not an official address mode, but supported by assembler (implicit #1)
+        AllowedAdrMode(DREG_ONLY, null, modInfo = RWM_MODIFY_OP1_OPSIZE, affectedCc = cc("***0*"), testedCc = cc("?----")),
     )
 
     private val BCHG_BCLR_BSET_MODES = listOf(
         AllowedAdrMode(DREG_ONLY, DREG_ONLY, OP_SIZE_L, modInfo = RWM_READ_OP1_B or RWM_MODIFY_OP2_L, affectedCc = cc("--*--")),
         AllowedAdrMode(DREG_ONLY, INDIRECT_MODES, OP_SIZE_B, modInfo = RWM_READ_OP1_B or RWM_MODIFY_OP2_B, affectedCc = cc("--*--")),
         AllowedAdrMode(setOf(AddressMode.IMMEDIATE_DATA), DREG_ONLY, OP_SIZE_L, modInfo = RWM_MODIFY_OP2_L, affectedCc = cc("--*--")),
-        AllowedAdrMode(setOf(AddressMode.IMMEDIATE_DATA), INDIRECT_MODES, OP_SIZE_B, modInfo = RWM_MODIFY_OP2_B, affectedCc = cc("--*--")),
+        AllowedAdrMode(setOf(AddressMode.IMMEDIATE_DATA), ALL_EXCEPT_AREG_AND_DREG, OP_SIZE_B, modInfo = RWM_MODIFY_OP2_B, affectedCc = cc("--*--")),
     )
 
     private val BTST_MODES = listOf(
         AllowedAdrMode(DREG_ONLY, DREG_ONLY, OP_SIZE_L, modInfo = RWM_READ_OP1_B or RWM_READ_OP2_L, affectedCc = cc("--*--")),
-        AllowedAdrMode(DREG_ONLY, INDIRECT_MODES, OP_SIZE_B, modInfo = RWM_READ_OP1_B or RWM_READ_OP2_B, affectedCc = cc("--*--")),
+        AllowedAdrMode(DREG_ONLY, ALL_EXCEPT_AREG_AND_DREG, OP_SIZE_B, modInfo = RWM_READ_OP1_B or RWM_READ_OP2_B, affectedCc = cc("--*--")),
         AllowedAdrMode(setOf(AddressMode.IMMEDIATE_DATA), DREG_ONLY, OP_SIZE_L, modInfo = RWM_READ_OP2_L, affectedCc = cc("--*--")),
-        AllowedAdrMode(setOf(AddressMode.IMMEDIATE_DATA), INDIRECT_MODES, OP_SIZE_B, modInfo = RWM_READ_OP2_B, affectedCc = cc("--*--")),
+        AllowedAdrMode(setOf(AddressMode.IMMEDIATE_DATA), ALL_EXCEPT_AREG_AND_DREG, OP_SIZE_B, modInfo = RWM_READ_OP2_B, affectedCc = cc("--*--")),
     )
 
     private val conditionCodes =
@@ -354,7 +372,9 @@ object M68kIsa {
                         AddressMode.ADDRESS_REGISTER_INDIRECT_POST_INC,
                         AddressMode.ADDRESS_REGISTER_INDIRECT_WITH_DISPLACEMENT,
                         AddressMode.ADDRESS_REGISTER_INDIRECT_WITH_INDEX,
-                        AddressMode.ABSOLUTE_ADDRESS
+                        AddressMode.ABSOLUTE_ADDRESS,
+                        AddressMode.PROGRAM_COUNTER_INDIRECT_WITH_DISPLACEMENT,
+                        AddressMode.PROGRAM_COUNTER_INDIRECT_WITH_INDEX
                     ),
                     setOf(AddressMode.IMMEDIATE_DATA),
                     OP_SIZE_WL,
@@ -944,5 +964,5 @@ object M68kIsa {
     private fun isAddressModeMatching(am: AllowedAdrMode, op1: AddressMode?, op2: AddressMode?, specialReg: String?) =
         ((((op1 == null) && (am.op1 == null)) || am.op1?.contains(op1) ?: false)
                 && (((op2 == null) && (am.op2 == null)) || am.op2?.contains(op2) ?: false)
-                && ((specialReg == null) || (specialReg == am.specialReg)))
+                && ((specialReg == null) || (specialReg.equals(am.specialReg, true))))
 }
\ No newline at end of file
diff --git a/src/main/resources/META-INF/plugin.xml b/src/main/resources/META-INF/plugin.xml
index 91d6776..a4e1cc8 100644
--- a/src/main/resources/META-INF/plugin.xml
+++ b/src/main/resources/META-INF/plugin.xml
@@ -16,7 +16,7 @@
 
     <extensions defaultExtensionNs="com.intellij">
         <fileType name="MC68000 Assembler" implementationClass="de.platon42.intellij.plugins.m68k.M68kFileType"
-                  fieldName="INSTANCE" language="MC68000" extensions="asm;ASM;s;S;i"/>
+                  fieldName="INSTANCE" language="MC68000" extensions="asm;s;i"/>
         <lang.parserDefinition language="MC68000"
                                implementationClass="de.platon42.intellij.plugins.m68k.parser.M68kParserDefinition"/>
         <lang.syntaxHighlighterFactory language="MC68000"
@@ -47,7 +47,7 @@
         <stubIndex implementation="de.platon42.intellij.plugins.m68k.stubs.M68kGlobalLabelStubIndex"/>
         <stubIndex implementation="de.platon42.intellij.plugins.m68k.stubs.M68kSymbolDefinitionStubIndex"/>
         <stubIndex implementation="de.platon42.intellij.plugins.m68k.stubs.M68kMacroDefinitionStubIndex"/>
-        <psi.referenceContributor implementation="de.platon42.intellij.plugins.m68k.refs.M68kReferenceContributor"/>
+        <psi.referenceContributor language="MC68000" implementation="de.platon42.intellij.plugins.m68k.refs.M68kReferenceContributor"/>
         <gotoSymbolContributor implementation="de.platon42.intellij.plugins.m68k.refs.M68kChooseByNameContributor"/>
         <renameInputValidator implementation="de.platon42.intellij.plugins.m68k.psi.M68kRenameInputValidator"/>
         <include.provider implementation="de.platon42.intellij.plugins.m68k.scanner.M68kIncludeFileProvider"/>
diff --git a/src/test/java/de/platon42/intellij/plugins/m68k/parser/AddressingModesTest.kt b/src/test/java/de/platon42/intellij/plugins/m68k/parser/AddressingModesTest.kt
index 9f907a0..c15b37d 100644
--- a/src/test/java/de/platon42/intellij/plugins/m68k/parser/AddressingModesTest.kt
+++ b/src/test/java/de/platon42/intellij/plugins/m68k/parser/AddressingModesTest.kt
@@ -87,6 +87,11 @@ internal class AddressingModesTest : AbstractParsingTest() {
         testGoodSyntax(testCase, " move.l 4.w,a6\n")
     }
 
+    @Test
+    internal fun btst_quirk(@MyTestCase testCase: ParsingTestExtension.IParsingTestCase) {
+        testGoodSyntax(testCase, " btst #5,#42\n btst d0,#42")
+    }
+
     @Test
     internal fun movem_register_list(@MyTestCase testCase: ParsingTestExtension.IParsingTestCase) {
         testGoodSyntax(testCase, " movem.l d0-d2/d4/a0/a2-a3/a5,-(sp)\n")
@@ -118,7 +123,7 @@ internal class AddressingModesTest : AbstractParsingTest() {
     internal fun special_register_move(@MyTestCase testCase: ParsingTestExtension.IParsingTestCase) {
         testGoodSyntax(
             testCase, " move.l usp,a0\n"
-                    + " move.l a5,usp\n"
+                    + " move.l a5,USP\n"
         )
     }
 
diff --git a/src/test/resources/parser/addressingmodes/btst_quirk.txt b/src/test/resources/parser/addressingmodes/btst_quirk.txt
new file mode 100644
index 0000000..f140baa
--- /dev/null
+++ b/src/test/resources/parser/addressingmodes/btst_quirk.txt
@@ -0,0 +1,31 @@
+Assembly File: a.asm
+  PsiWhiteSpace(' ')
+  M68kStatementImpl(STATEMENT)
+    M68kAsmInstructionImpl(ASM_INSTRUCTION)
+      M68kAsmOpImpl(ASM_OP)
+        PsiElement(M68kTokenType.MNEMONIC)('btst')
+      PsiWhiteSpace(' ')
+      M68kImmediateDataImpl(IMMEDIATE_DATA)
+        PsiElement(M68kTokenType.HASH)('#')
+        M68kLiteralExprImpl(LITERAL_EXPR)
+          PsiElement(M68kTokenType.DECIMAL)('5')
+      PsiElement(M68kTokenType.SEPARATOR)(',')
+      M68kImmediateDataImpl(IMMEDIATE_DATA)
+        PsiElement(M68kTokenType.HASH)('#')
+        M68kLiteralExprImpl(LITERAL_EXPR)
+          PsiElement(M68kTokenType.DECIMAL)('42')
+  PsiElement(M68kTokenType.EOL)('\n')
+  PsiWhiteSpace(' ')
+  M68kStatementImpl(STATEMENT)
+    M68kAsmInstructionImpl(ASM_INSTRUCTION)
+      M68kAsmOpImpl(ASM_OP)
+        PsiElement(M68kTokenType.MNEMONIC)('btst')
+      PsiWhiteSpace(' ')
+      M68kDataRegisterDirectAddressingModeImpl(DATA_REGISTER_DIRECT_ADDRESSING_MODE)
+        M68kDataRegisterImpl(DATA_REGISTER)
+          PsiElement(M68kTokenType.DREG)('d0')
+      PsiElement(M68kTokenType.SEPARATOR)(',')
+      M68kImmediateDataImpl(IMMEDIATE_DATA)
+        PsiElement(M68kTokenType.HASH)('#')
+        M68kLiteralExprImpl(LITERAL_EXPR)
+          PsiElement(M68kTokenType.DECIMAL)('42')
\ No newline at end of file
diff --git a/src/test/resources/parser/addressingmodes/special_register_move.txt b/src/test/resources/parser/addressingmodes/special_register_move.txt
index 76c0da8..3295685 100644
--- a/src/test/resources/parser/addressingmodes/special_register_move.txt
+++ b/src/test/resources/parser/addressingmodes/special_register_move.txt
@@ -29,5 +29,5 @@ Assembly File: a.asm
       PsiElement(M68kTokenType.SEPARATOR)(',')
       M68kSpecialRegisterDirectAddressingModeImpl(SPECIAL_REGISTER_DIRECT_ADDRESSING_MODE)
         M68kSpecialRegisterImpl(SPECIAL_REGISTER)
-          PsiElement(M68kTokenType.REG_USP)('usp')
+          PsiElement(M68kTokenType.REG_USP)('USP')
   PsiElement(M68kTokenType.EOL)('\n')
\ No newline at end of file