From a7cc770be8a009bff83b76bfbcc8521b6b8a616d Mon Sep 17 00:00:00 2001
From: Michel Heily <michelheily@gmail.com>
Date: Sat, 3 Jul 2021 22:09:32 +0300
Subject: [PATCH] arm: finish converting all instructions to const-generics

Former-commit-id: 4557ecffb89d563357f5bd769515254533a404ac
Former-commit-id: 8ce461f1b48ff5e7c72cdcd3069dcee0960dbc8e
---
 core/build.rs                 |  6 +++---
 core/src/arm7tdmi/arm/exec.rs | 28 ++++++++++++----------------
 2 files changed, 15 insertions(+), 19 deletions(-)

diff --git a/core/build.rs b/core/build.rs
index 4f520fb..21757a4 100644
--- a/core/build.rs
+++ b/core/build.rs
@@ -305,10 +305,10 @@ fn arm_decode(i: u32) -> (&'static str, String) {
                         let is_op_not_touching_rd = i.bit_range(21..25) & 0b1100 == 0b1000;
                         if !set_cond_flags && is_op_not_touching_rd {
                             if i.bit(21) {
-                                // Since bit-16 is ignored and we can't know statically if this is a exec_arm_transfer_to_status or exec_arm_transfer_to_status
-                                ("MoveToStatus", String::from("exec_arm_transfer_to_status"))
+                                ("MoveToStatus", format!("exec_arm_transfer_to_status::<{IMM}, {SPSR_FLAG}>",
+                                    IMM = i.bit(25), SPSR_FLAG = i.bit(22)))
                             } else {
-                                ("MoveFromStatus", String::from("exec_arm_mrs"))
+                                ("MoveFromStatus", format!("exec_arm_mrs::<{SPSR_FLAG}>", SPSR_FLAG = i.bit(22)))
                             }
                         } else {
                             ("DataProcessing", format!("exec_arm_data_processing::<{OP}, {IMM}, {SET_FLAGS}, {SHIFT_BY_REG}>",
diff --git a/core/src/arm7tdmi/arm/exec.rs b/core/src/arm7tdmi/arm/exec.rs
index 6974b66..f835a43 100644
--- a/core/src/arm7tdmi/arm/exec.rs
+++ b/core/src/arm7tdmi/arm/exec.rs
@@ -75,9 +75,9 @@ impl<I: MemoryInterface> Core<I> {
 
     /// Move from status register
     /// 1S
-    pub fn exec_arm_mrs(&mut self, insn: u32) -> CpuAction {
+    pub fn exec_arm_mrs<const SPSR_FLAG: bool>(&mut self, insn: u32) -> CpuAction {
         let rd = insn.bit_range(12..16) as usize;
-        let result = if insn.spsr_flag() {
+        let result = if SPSR_FLAG {
             self.spsr.get()
         } else {
             self.cpsr.get()
@@ -87,9 +87,13 @@ impl<I: MemoryInterface> Core<I> {
         CpuAction::AdvancePC(Seq)
     }
 
-    #[inline(always)]
-    fn decode_msr_param(&mut self, insn: u32) -> u32 {
-        if insn.bit(25) {
+    /// Move to status register
+    /// 1S
+    pub fn exec_arm_transfer_to_status<const IMM: bool, const SPSR_FLAG: bool>(
+        &mut self,
+        insn: u32,
+    ) -> CpuAction {
+        let value = if IMM {
             let immediate = insn & 0xff;
             let rotate = 2 * insn.bit_range(8..12);
             let mut carry = self.cpsr.C();
@@ -98,13 +102,7 @@ impl<I: MemoryInterface> Core<I> {
             v
         } else {
             self.get_reg((insn & 0b1111) as usize)
-        }
-    }
-
-    /// Move to status register
-    /// 1S
-    pub fn exec_arm_transfer_to_status(&mut self, insn: u32) -> CpuAction {
-        let value = self.decode_msr_param(insn);
+        };
 
         let f = insn.bit(19);
         let s = insn.bit(18);
@@ -125,17 +123,15 @@ impl<I: MemoryInterface> Core<I> {
             mask |= 0xff << 0;
         }
 
-        let is_spsr = insn.spsr_flag();
-
         match self.cpsr.mode() {
             CpuMode::User => {
-                if is_spsr {
+                if SPSR_FLAG {
                     panic!("User mode can't access SPSR")
                 }
                 self.cpsr.set_flag_bits(value);
             }
             _ => {
-                if is_spsr {
+                if SPSR_FLAG {
                     self.spsr.set(value);
                 } else {
                     let old_mode = self.cpsr.mode();