diff --git a/src/disasm.rs b/src/disasm.rs
index ddce5e1..feb6edf 100644
--- a/src/disasm.rs
+++ b/src/disasm.rs
@@ -204,6 +204,8 @@ impl Disassembler {
     }
 
     /// Match the modrm reg bits to the GPR1 mnemonics.
+    /// GPR always has an imm value as second operand, but is available in both
+    /// Byte and Word length.
     pub fn modrm_reg_to_mnemonic(reg: u8, target: ModRmTarget, imm: OperandWidth) -> Mnemonic {
         match imm {
             OperandWidth::Byte(b) => match reg {
diff --git a/src/disasm_macros.rs b/src/disasm_macros.rs
index a5998ac..022c81d 100644
--- a/src/disasm_macros.rs
+++ b/src/disasm_macros.rs
@@ -26,7 +26,8 @@ macro_rules! modrms {
 }
 
 #[macro_export]
-/// Generate a GPR instruction from modrm byte for byte
+/// Generate a GPR instruction from modrm byte for byte.
+/// GPR always has an imm value as second operand.
 macro_rules! modrmgprb {
     ($self:ident) => {{
         let (target, reg) = $self.parse_modrm_byte(OperandWidth::Byte(0));
@@ -37,10 +38,11 @@ macro_rules! modrmgprb {
 
 #[macro_export]
 /// Generate a GPR instruction from modrm byte for word
+/// GPR always has an imm value as second operand.
 macro_rules! modrmgprv {
     ($self:ident) => {{
         let (target, reg) = $self.parse_modrm_byte(OperandWidth::Word(0));
-        let imm = $self.parse_byte();
-        Self::modrm_reg_to_mnemonic(reg, target, OperandWidth::Word(imm.into()))
+        let imm = $self.parse_word();
+        Self::modrm_reg_to_mnemonic(reg, target, OperandWidth::Word(imm))
     }};
 }