diff --git a/src/assembler/instructions.c b/src/assembler/instructions.c
index 54ff6ef..714e890 100644
--- a/src/assembler/instructions.c
+++ b/src/assembler/instructions.c
@@ -156,10 +156,7 @@ static ASMErrorDesc parse_arg(
     USE_PARSER(register, AT_REGISTER, reg)
     USE_PARSER(immediate, AT_IMMEDIATE, imm)
     USE_PARSER(indirect, AT_INDIRECT, indirect)
-
-    // AT_INDEXED
-    // ASMArgIndexed index;
-
+    USE_PARSER(indexed, AT_INDEXED, index)
     USE_PARSER(condition, AT_CONDITION, cond)
 
     // AT_LABEL
@@ -202,7 +199,7 @@ static ASMErrorDesc parse_args(
         } else {
             if ((c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') ||
                  c == ' ' || c == '+' || c == '-' || c == '(' || c == ')' ||
-                 c == '_' || c == '.')
+                 c == '$' || c == '_' || c == '.')
                 i++;
             else
                 return ED_PS_ARG_SYNTAX;
@@ -352,8 +349,6 @@ ASMInstParser get_inst_parser(char mstr[MAX_MNEMONIC_SIZE])
     // single 32-bit value to do fast lookups:
     uint32_t key = (mstr[0] << 24) + (mstr[1] << 16) + (mstr[2] << 8) + mstr[3];
 
-    DEBUG("get_inst_parser(): -->%.*s<-- 0x%08X", MAX_MNEMONIC_SIZE, mstr, key)
-
     HANDLE(nop)
     HANDLE(inc)
     HANDLE(add)
diff --git a/src/assembler/parse_util.c b/src/assembler/parse_util.c
index 3c9f3bb..d69f792 100644
--- a/src/assembler/parse_util.c
+++ b/src/assembler/parse_util.c
@@ -25,6 +25,37 @@
 */
 
 /*
+    Adjust *arg_ptr / *size_ptr for an indirect argument, like (hl) or (ix+*).
+
+    *size_ptr must be > 2 to begin with, and is assured to be > 0 on success.
+    The two arguments are not modified on failure.
+*/
+static bool adjust_for_indirection(const char **arg_ptr, ssize_t *size_ptr)
+{
+    const char *arg = *arg_ptr;
+    ssize_t size = *size_ptr;
+
+    if (arg[0] != '(' || arg[size - 1] != ')')
+        return false;
+    arg++;
+    size -= 2;
+
+    if (arg[0] == ' ') {
+        arg++;
+        if (--size <= 0)
+            return false;
+    }
+    if (arg[size - 1] == ' ') {
+        if (--size <= 0)
+            return false;
+    }
+
+    *arg_ptr = arg;
+    *size_ptr = size;
+    return true;
+}
+
+/*
     Read in a boolean value and store it in *result.
 */
 bool parse_bool(bool *result, const char *arg, ssize_t size)
@@ -283,10 +314,10 @@ bool argparse_immediate(ASMArgImmediate *result, const char *arg, ssize_t size)
     }
 
     uint32_t uval;
-    if (!parse_uint32_t(&uval, arg, size) || uval > UINT16_MAX)
+    if (!parse_uint32_t(&uval, arg + i, size - i) || uval > UINT16_MAX)
         return false;
 
-    int32_t sval = negative ? uval : -uval;
+    int32_t sval = negative ? -uval : uval;
     if (sval < INT16_MIN)
         return false;
 
@@ -294,15 +325,19 @@ bool argparse_immediate(ASMArgImmediate *result, const char *arg, ssize_t size)
     result->sval = sval;
     result->mask = 0;
 
-    if (negative) {
-        if (sval >= INT8_MIN && sval <= INT8_MAX)
+    if (sval < 0) {
+        if (sval >= INT8_MIN)
             result->mask |= IMM_S8;
-        if (sval >= INT8_MIN + 2 && sval <= INT8_MAX + 2)
+        if (sval >= INT8_MIN + 2)
             result->mask |= IMM_REL;
     } else {
         result->mask = IMM_U16;
         if (uval <= UINT8_MAX)
             result->mask |= IMM_U8;
+        if (uval <= INT8_MAX)
+            result->mask |= IMM_S8;
+        if (uval <= INT8_MAX + 2)
+            result->mask |= IMM_REL;
         if (uval <= 7)
             result->mask |= IMM_BIT;
         if (!(uval & ~0x38))
@@ -318,12 +353,8 @@ bool argparse_immediate(ASMArgImmediate *result, const char *arg, ssize_t size)
 */
 bool argparse_indirect(ASMArgIndirect *result, const char *arg, ssize_t size)
 {
-    if (size < 3)
-        return false;
-    if (arg[0] != '(' || arg[size - 1] != ')')
+    if (size < 3 || !adjust_for_indirection(&arg, &size))
         return false;
-    arg++;
-    size -= 2;
 
     ASMArgRegister reg;
     ASMArgImmediate imm;
@@ -344,6 +375,43 @@ bool argparse_indirect(ASMArgIndirect *result, const char *arg, ssize_t size)
 }
 
 /*
+    Read in an indexed argument and store it in *result.
+*/
+bool argparse_indexed(ASMArgIndexed *result, const char *arg, ssize_t size)
+{
+    if (size < 4 || !adjust_for_indirection(&arg, &size) || size < 2)
+        return false;
+
+    ASMArgRegister reg;
+    if (arg[0] != 'i')
+        return false;
+    if (arg[1] == 'x')
+        reg = REG_IX;
+    else if (arg[1] == 'y')
+        reg = REG_IY;
+    else
+        return false;
+
+    arg += 2;
+    size -= 2;
+    if (size > 0 && arg[0] == ' ') {
+        arg++;
+        size--;
+    }
+
+    if (size > 0) {
+        ASMArgImmediate imm;
+        if (!argparse_immediate(&imm, arg, size) || !(imm.mask & IMM_S8))
+            return false;
+        result->offset = imm.sval;
+    } else {
+        result->offset = 0;
+    }
+    result->reg = reg;
+    return true;
+}
+
+/*
     Read in a boolean argument from the given line and store it in *result.
 */
 DIRECTIVE_PARSE_FUNC(bool, bool)
diff --git a/src/assembler/parse_util.h b/src/assembler/parse_util.h
index 588220d..85bdf86 100644
--- a/src/assembler/parse_util.h
+++ b/src/assembler/parse_util.h
@@ -24,6 +24,7 @@ bool argparse_register(ASMArgRegister*, const char*, ssize_t);
 bool argparse_condition(ASMArgCondition*, const char*, ssize_t);
 bool argparse_immediate(ASMArgImmediate*, const char*, ssize_t);
 bool argparse_indirect(ASMArgIndirect*, const char*, ssize_t);
+bool argparse_indexed(ASMArgIndexed*, const char*, ssize_t);
 
 /* Preprocessor directive parsers */
 bool dparse_bool(bool*, const ASMLine*, const char*);