Make PIF stuff a little less annoying to read

src/backend/core/mmio/PI.cpp

@@ -466,19 +466,19 @@ u32 PI::AccessTiming(const u8 domain, const u32 length) const {
     latency = piBsdDom1Lat + 1;
     pulse_width = piBsdDom1Pwd + 1;
     release = piBsdDom1Rls + 1;
-    page_size = std::pow(2, (piBsdDom1Pgs + 2));
+    page_size = 1 << (piBsdDom1Pgs + 2);
     break;
   case 2:
     latency = piBsdDom2Lat + 1;
     pulse_width = piBsdDom2Pwd + 1;
     release = piBsdDom2Rls + 1;
-    page_size = std::pow(2, (piBsdDom2Pgs + 2));
+    page_size = 1 << (piBsdDom2Pgs + 2);
     break;
   default:
     panic("Unknown PI domain: {}\n", domain);
   }
 
-  const uint32_t pages = ceil(static_cast<double>(length) / page_size);
+  const uint32_t pages = static_cast<uint32_t>(ceil(static_cast<double>(length) / static_cast<double>(page_size)));
 
   cycles += (14 + latency) * pages;
   cycles += (pulse_width + release) * (length / 2);
@@ -492,8 +492,8 @@ void PI::DMA<false>() {
   const s32 len = rdLen + 1;
   trace("PI DMA from RDRAM to CARTRIDGE (size: {} B, {:08X} to {:08X})", len, dramAddr, cartAddr);
 
-  if (mem.saveType == SAVE_FLASH_1m && cartAddr >= SREGION_PI_SRAM && cartAddr < 0x08010000) {
+  if (mem.saveType == SAVE_FLASH_1m && cartAddr >= SREGION_PI_SRAM && cartAddr < (CART_REGION_START_2_2 + 1_mb)) {
-    cartAddr = SREGION_PI_SRAM | ((cartAddr & 0xFFFFF) << 1);
+    cartAddr = SREGION_PI_SRAM | ((cartAddr & (1_mb-1)) << 1);
   }
 
   for (int i = 0; i < len; i++) {
@@ -515,8 +515,8 @@ void PI::DMA<true>() {
   const s32 len = wrLen + 1;
   trace("PI DMA from CARTRIDGE to RDRAM (size: {} B, {:08X} to {:08X})", len, cartAddr, dramAddr);
 
-  if (mem.saveType == SAVE_FLASH_1m && cartAddr >= SREGION_PI_SRAM && cartAddr < 0x08010000) {
+  if (mem.saveType == SAVE_FLASH_1m && cartAddr >= SREGION_PI_SRAM && cartAddr < (CART_REGION_START_2_2 + 1_mb)) {
-    cartAddr = SREGION_PI_SRAM | ((cartAddr & 0xFFFFF) << 1);
+    cartAddr = SREGION_PI_SRAM | ((cartAddr & (1_mb-1)) << 1);
   }
 
   for (u32 i = 0; i < len; i++) {

src/backend/core/mmio/PIF.cpp

@@ -125,7 +125,7 @@ void PIF::LoadEeprom(const SaveType saveType, const std::string &path) {
   }
 }
 
-enum CMDIndexes { CMD_LEN = 0, CMD_RES_LEN, CMD_IDX, CMD_START };
+enum CommandIndexes { COMMAND_LEN = 0, COMMAND_RESULT_LEN, COMMAND_INDEX, COMMAND_START };
 
 void PIF::CICChallenge() {
   u8 challenge[30];
@@ -167,28 +167,32 @@ FORCE_INLINE u8 DataCRC(const u8 *data) {
 #define BCD_ENCODE(x) (((x) / 10) << 4 | ((x) % 10))
 #define BCD_DECODE(x) (((x) >> 4) * 10 + ((x) & 15))
 
-void PIF::ProcessCommands(const Mem &mem) {
+void PIF::ConfigureJoyBusFrame(const Mem& mem) {
-  const u8 control = ram[63];
-  if (control & 1) {
   channel = 0;
   int i = 0;
   while (i < 63) {
-      u8 *cmd = &ram[i++];
+    u8 *packet = &ram[i++];
+    const u8& commandLength = packet[COMMAND_LEN] & 0x3F;
 
-      if (const u8 cmdlen = cmd[CMD_LEN] & 0x3F; cmdlen == 0 || cmdlen == 0x3D) {
+    if (commandLength == 0) {
       channel++;
-      } else if (cmdlen == 0x3E) {
+    } else if (commandLength == 0x3D) {
+      channel = 0;
+      channel++;
+    } else if (commandLength == 0x3E) {
       break;
-      } else if (cmdlen == 0x3F) {
+    } else if (commandLength == 0x3F) {
+      continue;
     } else {
       const u8 r = ram[i++];
       if (r == 0xFE) {
         break;
       }
       const u8 reslen = r & 0x3F;
-        u8 *res = &ram[i + cmdlen];
+      u8 *res = &ram[i + commandLength];
+      const u8& commandIndex = packet[COMMAND_INDEX];
 
-        switch (cmd[CMD_IDX]) {
+      switch (commandIndex) {
         case 0:
         case 0xff:
           ControllerID(res);
@@ -196,29 +200,30 @@ void PIF::ProcessCommands(const Mem &mem) {
           break;
         case 1:
           if (!ReadButtons(res)) {
-            cmd[1] |= 0x80;
+            packet[COMMAND_RESULT_LEN] |= 0x80;
           }
           channel++;
           break;
         case 2:
-          MempakRead(cmd, res);
+          MempakRead(packet, res);
           break;
         case 3:
-          MempakWrite(cmd, res);
+          MempakWrite(packet, res);
           break;
         case 4:
-          EepromRead(cmd, res, mem);
+          EepromRead(packet, res, mem);
           break;
         case 5:
-          EepromWrite(cmd, res, mem);
+          EepromWrite(packet, res, mem);
           break;
         case 6:
           res[0] = 0x00;
           res[1] = 0x10;
           res[2] = 0x80;
           break;
-        case 7:
+        case 7: {
-          switch (cmd[CMD_START]) {
+          const u8& commandStart = packet[COMMAND_START];
+          switch (commandStart) {
             case 0:
             case 1:
             case 3:
@@ -235,21 +240,29 @@ void PIF::ProcessCommands(const Mem &mem) {
                 res[5] = BCD_ENCODE(gmtm->tm_mon);
                 res[6] = BCD_ENCODE(gmtm->tm_year);
                 res[7] = (gmtm->tm_year - 1900) >= 100 ? 1 : 0;
+                res[8] = 0x80;
               }
               break;
             default:
-            panic("Invalid read RTC block {}", cmd[CMD_START]);
+              panic("Invalid read RTC block {}", commandStart);
           }
-          break;
+        } break;
         case 8:
+          res[0] = 0x00;
           break;
         default:
-          panic("Invalid PIF command: {:X}", cmd[2]);
+          panic("Invalid PIF command: {:X}", commandIndex);
       }
 
-        i += cmdlen + reslen;
+      i += commandLength + reslen;
     }
   }
+}
+
+void PIF::ProcessCommands(const Mem &mem) {
+  const u8 control = ram[63];
+  if (control & 1) {
+    ConfigureJoyBusFrame(mem);
   }
 
   if (control & 0x02) {

src/backend/core/mmio/PIF.hpp

@@ -235,5 +235,7 @@ struct PIF {
 
     return joybusDevices[channel].accessoryType;
   }
+private:
+  void ConfigureJoyBusFrame(const Mem &);
 };
 } // namespace n64