control, gpr register names, readme

1 files changed, 12 insertions, 1 deletions

diff --git a/src/display.rs b/src/display.rs
index b17cc90..fd9c101 100644
--- a/src/display.rs
+++ b/src/display.rs
@@ -935,7 +935,18 @@ impl fmt::Display for Operand {
                 write!(f, "$+#{}", rel)
             }
             Operand::Gpr { reg } => {
-                write!(f, "R{}", reg)
+                const NAMES: [&'static str; 32] = [
+                    "R0", "R1", "R2", "R3", "R4", "R5", "R6", "R7",
+                    "R8", "R9", "R10", "R11", "R12", "R13", "R14", "R15",
+                    "R16", "R17", "R18", "R19", "R20", "R21", "R22", "R23",
+                    "R24", "R25", "R26", "R27",
+                    // the three R29 through R31 general registers support subroutines and the Software
+                    // Stack. ... they have symbol aliases that indicate when these registers are accessed
+                    // as subroutine and stack registers (V73 Section 2.1)
+                    "R28", "SP", "FP", "LR",
+                ];
+
+                f.write_str(NAMES[*reg as usize])
             }
             Operand::Cr { reg } => {
                 // V69 Table 2-2 Aliased control registers