Implement NO$GBA debug registers. (#1110)

* Implement NO$GBA debug registers.

NO$GBA comes with 4 debug registers that allow a ROM to print text to
the emulator terminal and 2 other status registers, one with the name of the
emulator and the other with the clock cycles count. This commit
implements them for the ARMv5 processor.

Some small things to note:
 - `NocashPrint` was changed and now it takes an address to _the string_ instead of the flags before it (those
don't do anything anyways).
 - The "Emulation ID" register contains the string "melonDS " followed by version, _not_ "NO$GBA"

* Fix styling issue and improve comment regarding NO$GBA message flags

1 files changed, 8 insertions, 2 deletions

diff --git a/src/ARMInterpreter_ALU.cpp b/src/ARMInterpreter_ALU.cpp
index d72a5db..92d1571 100644
--- a/src/ARMInterpreter_ALU.cpp
+++ b/src/ARMInterpreter_ALU.cpp
@@ -661,7 +661,10 @@ void A_MOV_REG_LSL_IMM_DBG(ARM* cpu)
         (cpu->NextInstr[0] & 0xFF000000) == 0xEA000000 && // branch
         (cpu->NextInstr[1] & 0xFFFF) == 0x6464)
     {
-        u32 addr = cpu->R[15] + 2;
+        // GBATek says the two bytes after the 2nd ID are _reserved_ for flags
+        // but since they serve no purpose ATTOW, we can skip them
+        u32 addr = cpu->R[15] + 4; // Skip 2nd ID and flags
+        // TODO: Pass flags to NocashPrint
         NDS::NocashPrint(cpu->Num, addr);
     }
 }
@@ -1527,7 +1530,10 @@ void T_MOV_HIREG(ARM* cpu)
         (cpu->NextInstr[0] & 0xF800) == 0xE000 && // branch
         (cpu->NextInstr[1] & 0xFFFF) == 0x6464)
     {
-        u32 addr = cpu->R[15] + 2;
+        // GBATek says the two bytes after the 2nd ID are _reserved_ for flags
+        // but since they serve no purpose ATTOW, we can skip them
+        u32 addr = cpu->R[15] + 4; // Skip 2nd ID and flags
+        // TODO: Pass flags to NocashPrint
         NDS::NocashPrint(cpu->Num, addr);
     }
 }