diff --git a/include/ultra64.h b/include/ultra64.h
index d309026b97..49323cc2bd 100644
--- a/include/ultra64.h
+++ b/include/ultra64.h
@@ -11,6 +11,7 @@
 #include "ultra64/sptask.h"
 #include "ultra64/thread.h"
 #include "ultra64/rcp.h"
+#include "ultra64/rdp.h"
 #include "ultra64/rsp.h"
 #include "ultra64/vi.h"
 
diff --git a/include/ultra64/hardware.h b/include/ultra64/hardware.h
index c3eb8dd4cb..ae6470d51d 100644
--- a/include/ultra64/hardware.h
+++ b/include/ultra64/hardware.h
@@ -96,6 +96,7 @@
 #define SI_STATUS_INTERRUPT     (1 << 12)
 
 #define PIF_RAM_START  0x1FC007C0
+#define PIF_RAM_SIZE   0x40
 
 #define MI_INIT_MODE_REG  0x04300000
 #define MI_MODE_REG       MI_INIT_MODE_REG
diff --git a/include/ultra64/rdp.h b/include/ultra64/rdp.h
new file mode 100644
index 0000000000..b4b3bb532f
--- /dev/null
+++ b/include/ultra64/rdp.h
@@ -0,0 +1,45 @@
+#ifndef ULTRA64_RDP_H
+#define ULTRA64_RDP_H
+
+/* DP Command Registers */
+#define DPC_START_REG    0x04100000
+#define DPC_END_REG      0x04100004
+#define DPC_CURRENT_REG  0x04100008
+#define DPC_STATUS_REG   0x0410000C
+#define DPC_CLOCK_REG    0x04100010
+#define DPC_BUFBUSY_REG  0x04100014
+#define DPC_PIPEBUSY_REG 0x04100018
+#define DPC_TMEM_REG     0x0410001C
+
+/* DP Span Registers */
+#define DPS_TBIST_REG        0x04200000
+#define DPS_TEST_MODE_REG    0x04200004
+#define DPS_BUFTEST_ADDR_REG 0x04200008
+#define DPS_BUFTEST_DATA_REG 0x0420000C
+
+/* DP Status Read Flags */
+#define DPC_STATUS_XBUS_DMEM_DMA    (1 <<  0)
+#define DPC_STATUS_FREEZE           (1 <<  1)
+#define DPC_STATUS_FLUSH            (1 <<  2)
+#define DPC_STATUS_START_GCLK       (1 <<  3)
+#define DPC_STATUS_TMEM_BUSY        (1 <<  4)
+#define DPC_STATUS_PIPE_BUSY        (1 <<  5)
+#define DPC_STATUS_CMD_BUSY         (1 <<  6)
+#define DPC_STATUS_CBUF_READY       (1 <<  7)
+#define DPC_STATUS_DMA_BUSY         (1 <<  8)
+#define DPC_STATUS_END_VALID        (1 <<  9)
+#define DPC_STATUS_START_VALID      (1 << 10)
+
+/* DP Status Write Flags */
+#define DPC_CLR_XBUS_DMEM_DMA   (1 << 0)
+#define DPC_SET_XBUS_DMEM_DMA   (1 << 1)
+#define DPC_CLR_FREEZE          (1 << 2)
+#define DPC_SET_FREEZE          (1 << 3)
+#define DPC_CLR_FLUSH           (1 << 4)
+#define DPC_SET_FLUSH           (1 << 5)
+#define DPC_CLR_TMEM_CTR        (1 << 6)
+#define DPC_CLR_PIPE_CTR        (1 << 7)
+#define DPC_CLR_CMD_CTR         (1 << 8)
+#define DPC_CLR_CLOCK_CTR       (1 << 9)
+
+#endif
diff --git a/include/variables.h b/include/variables.h
index 93b7790cb2..6249405258 100644
--- a/include/variables.h
+++ b/include/variables.h
@@ -8,7 +8,7 @@
 // pre-boot variables
 extern u32 osTvType;
 extern u32 osRomType;
-extern u32 osRomBase;
+extern uintptr_t osRomBase;
 extern u32 osResetType;
 extern u32 osCicId;
 extern u32 osVersion;
diff --git a/spec b/spec
index 2983af4dc4..c9458d9390 100644
--- a/spec
+++ b/spec
@@ -170,7 +170,7 @@ beginseg
     include "build/src/libultra/voice/voicecontwrite20.o"
     include "build/src/libultra/io/crc.o"
     include "build/src/libultra/os/getactivequeue.o"
-    include "build/src/libultra/gu/normalize.o"
+    include "build/asm/boot/normalize.text.o"
     include "build/asm/boot/setcompare.text.o"
     include "build/asm/boot/getcompare.text.o"
     include "build/src/libultra/io/dpgetstat.o"
diff --git a/src/libultra/gu/normalize.c b/src/libultra/gu/normalize.c
deleted file mode 100644
index 3fdbbe880a..0000000000
--- a/src/libultra/gu/normalize.c
+++ /dev/null
@@ -1,3 +0,0 @@
-#include "global.h"
-
-#pragma GLOBAL_ASM("asm/non_matchings/boot/normalize/guNormalize.s")
diff --git a/src/libultra/io/aigetlen.c b/src/libultra/io/aigetlen.c
index e3e7289aca..58d8db4875 100644
--- a/src/libultra/io/aigetlen.c
+++ b/src/libultra/io/aigetlen.c
@@ -1,5 +1,5 @@
 #include "global.h"
 
 u32 osAiGetLength(void) {
-    return *(u32*)0xA4500004;
+    return HW_REG(AI_LEN_REG, u32);
 }
diff --git a/src/libultra/io/aisetfreq.c b/src/libultra/io/aisetfreq.c
index ef0a8d2deb..8702941b9a 100644
--- a/src/libultra/io/aisetfreq.c
+++ b/src/libultra/io/aisetfreq.c
@@ -1,3 +1,20 @@
 #include "global.h"
 
-#pragma GLOBAL_ASM("asm/non_matchings/boot/aisetfreq/osAiSetFrequency.s")
+s32 osAiSetFrequency(u32 frequency) {
+    u8 bitrate;
+    f32 dacRateF = ((f32)osViClock / frequency) + 0.5f;
+    u32 dacRate = dacRateF;
+
+    if (dacRate < 132) {
+        return -1;
+    }
+
+    bitrate = (dacRate / 66);
+    if (bitrate > 16) {
+        bitrate = 16;
+    }
+
+    HW_REG(AI_DACRATE_REG, u32) = dacRate - 1;
+    HW_REG(AI_BITRATE_REG, u32) = bitrate - 1;
+    return osViClock / (s32)dacRate;
+}
diff --git a/src/libultra/io/crc.c b/src/libultra/io/crc.c
index e2f3fb9912..acae7b4081 100644
--- a/src/libultra/io/crc.c
+++ b/src/libultra/io/crc.c
@@ -34,7 +34,7 @@
  * \f[ m(X) X^n = Q(X) p(X) + R(X) \f]
  * (\f$ R(X) \f$ is the *remainder after dividing by \f$ p(X) \f$*).
  * - Therefore, \f$ m(X) X^n - R(X) \f$ is divisible by the generator polynomial. This means that if we append the
- * binary number corresponding to \f$ R(X) \f$ to the message and rerun the algorithm, we will get 0 if now errors have
+ * binary number corresponding to \f$ R(X) \f$ to the message and rerun the algorithm, we will get 0 if no errors have
  * been introduced.
  *
  *
diff --git a/src/libultra/io/dpgetstat.c b/src/libultra/io/dpgetstat.c
index 763c6622e4..0c4b3073ba 100644
--- a/src/libultra/io/dpgetstat.c
+++ b/src/libultra/io/dpgetstat.c
@@ -1,5 +1,5 @@
 #include "global.h"
 
 u32 osDpGetStatus(void) {
-    return *(u32*)0xA410000C;
+    return HW_REG(DPC_STATUS_REG, u32);
 }
diff --git a/src/libultra/io/dpsetstat.c b/src/libultra/io/dpsetstat.c
index c653a08173..d2655626c6 100644
--- a/src/libultra/io/dpsetstat.c
+++ b/src/libultra/io/dpsetstat.c
@@ -1,5 +1,5 @@
 #include "global.h"
 
 void osDpSetStatus(u32 data) {
-    *(u32*)0xA410000C = data;
+    HW_REG(DPC_STATUS_REG, u32) = data;
 }
diff --git a/src/libultra/io/pirawdma.c b/src/libultra/io/pirawdma.c
index 242a91c24e..07aa1b8221 100644
--- a/src/libultra/io/pirawdma.c
+++ b/src/libultra/io/pirawdma.c
@@ -1,23 +1,22 @@
 #include "global.h"
 
-s32 __osPiRawStartDma(s32 direction, u32 devAddr, void* dramAddr, size_t size) {
-    register int stat;
+s32 __osPiRawStartDma(s32 direction, uintptr_t devAddr, void* dramAddr, size_t size) {
+    register int status = HW_REG(PI_STATUS_REG, u32);
 
-    stat = *(vu32*)0xA4600010;
-    while (stat & (2 | 1)) {
-        stat = *(vu32*)0xA4600010;
+    while (status & (PI_STATUS_IOBUSY | PI_STATUS_BUSY)) {
+        status = HW_REG(PI_STATUS_REG, u32);
     }
 
-    *(u32*)0xA4600000 = osVirtualToPhysical(dramAddr);
+    HW_REG(PI_DRAM_ADDR_REG, u32) = osVirtualToPhysical(dramAddr);
 
-    *(u32*)0xA4600004 = ((osRomBase | devAddr) & 0x1fffffff);
+    HW_REG(PI_CART_ADDR_REG, u32) = ((osRomBase | devAddr) & 0x1FFFFFFF);
 
     switch (direction) {
-        case 0:
-            *(u32*)0xA460000C = size - 1;
+        case OS_READ:
+            HW_REG(PI_WR_LEN_REG, u32) = size - 1;
             break;
-        case 1:
-            *(u32*)0xA4600008 = size - 1;
+        case OS_WRITE:
+            HW_REG(PI_RD_LEN_REG, u32) = size - 1;
             break;
         default:
             return -1;
diff --git a/src/libultra/io/si.c b/src/libultra/io/si.c
index 6de5874b90..563c682765 100644
--- a/src/libultra/io/si.c
+++ b/src/libultra/io/si.c
@@ -1,11 +1,11 @@
 #include "global.h"
 
-int __osSiDeviceBusy() {
-    register u32 status;
-    status = *(u32*)0xA4800018;
-    if (status & 3) {
-        return 1;
+s32 __osSiDeviceBusy() {
+    register u32 status = HW_REG(SI_STATUS_REG, u32);
+
+    if (status & (SI_STATUS_DMA_BUSY | SI_STATUS_IO_READ_BUSY)) {
+        return true;
     } else {
-        return 0;
+        return false;
     }
 }
diff --git a/src/libultra/io/sirawdma.c b/src/libultra/io/sirawdma.c
index ff57e21c23..eb62fa2a30 100644
--- a/src/libultra/io/sirawdma.c
+++ b/src/libultra/io/sirawdma.c
@@ -1,24 +1,24 @@
 #include "global.h"
 
 s32 __osSiRawStartDma(s32 direction, void* dramAddr) {
-    if ((*(u32*)0xA4800018 & 0x3) != 0) {
+    if (HW_REG(SI_STATUS_REG, u32) & (SI_STATUS_DMA_BUSY | SI_STATUS_IO_READ_BUSY)) {
         return -1;
     }
 
-    if (direction == 1) {
-        osWritebackDCache(dramAddr, 64);
+    if (direction == OS_WRITE) {
+        osWritebackDCache(dramAddr, PIF_RAM_SIZE);
     }
 
-    *(u32*)0xA4800000 = osVirtualToPhysical(dramAddr);
+    HW_REG(SI_DRAM_ADDR_REG, u32) = osVirtualToPhysical(dramAddr);
 
-    if (direction == 0) {
-        *(u32*)0xA4800004 = 0x1FC007C0;
+    if (direction == OS_READ) {
+        HW_REG(SI_PIF_ADDR_RD64B_REG, void*) = (void*)PIF_RAM_START;
     } else {
-        *(u32*)0xA4800010 = 0x1FC007C0;
+        HW_REG(SI_PIF_ADDR_WR64B_REG, void*) = (void*)PIF_RAM_START;
     }
 
-    if (direction == 0) {
-        osInvalDCache(dramAddr, 64);
+    if (direction == OS_READ) {
+        osInvalDCache(dramAddr, PIF_RAM_SIZE);
     }
     return 0;
 }
diff --git a/src/libultra/io/sp.c b/src/libultra/io/sp.c
index db2e5b4511..c028c76927 100644
--- a/src/libultra/io/sp.c
+++ b/src/libultra/io/sp.c
@@ -5,6 +5,7 @@ s32 __osSpDeviceBusy(void) {
 
     if (status & (SP_STATUS_DMA_BUSY | SP_STATUS_DMA_FULL | SP_STATUS_IO_FULL)) {
         return true;
+    } else {
+        return false;
     }
-    return false;
 }
diff --git a/src/libultra/io/spgetstat.c b/src/libultra/io/spgetstat.c
index 98a3dc23b6..8987b2414a 100644
--- a/src/libultra/io/spgetstat.c
+++ b/src/libultra/io/spgetstat.c
@@ -1,5 +1,5 @@
 #include "global.h"
 
 u32 __osSpGetStatus() {
-    return *(vu32*)0xA4040010;
+    return HW_REG(SP_STATUS_REG, u32);
 }
diff --git a/src/libultra/io/sprawdma.c b/src/libultra/io/sprawdma.c
index 95395a29d5..494f3db50d 100644
--- a/src/libultra/io/sprawdma.c
+++ b/src/libultra/io/sprawdma.c
@@ -1,17 +1,17 @@
 #include "global.h"
 
 s32 __osSpRawStartDma(s32 direction, void* devAddr, void* dramAddr, size_t size) {
-    if (__osSpDeviceBusy() != 0) {
+    if (__osSpDeviceBusy()) {
         return -1;
     }
 
-    *(vu32*)0xA4040000 = devAddr;
-    *(vu32*)0xA4040004 = osVirtualToPhysical(dramAddr);
+    HW_REG(SP_MEM_ADDR_REG, u32) = devAddr;
+    HW_REG(SP_DRAM_ADDR_REG, u32) = osVirtualToPhysical(dramAddr);
 
-    if (direction == 0) {
-        *(vu32*)0xA404000C = size - 1;
+    if (direction == OS_READ) {
+        HW_REG(SP_WR_LEN_REG, u32) = size - 1;
     } else {
-        *(vu32*)0xA4040008 = size - 1;
+        HW_REG(SP_RD_LEN_REG, u32) = size - 1;
     }
 
     return 0;
diff --git a/src/libultra/io/spsetstat.c b/src/libultra/io/spsetstat.c
index 346577218d..eb183eab47 100644
--- a/src/libultra/io/spsetstat.c
+++ b/src/libultra/io/spsetstat.c
@@ -1,5 +1,5 @@
 #include "global.h"
 
 void __osSpSetStatus(u32 data) {
-    *(vu32*)0xA4040010 = data;
+    HW_REG(SP_STATUS_REG, u32) = data;
 }
diff --git a/src/libultra/io/vi.c b/src/libultra/io/vi.c
index 7b64b4449b..ec0b1de700 100644
--- a/src/libultra/io/vi.c
+++ b/src/libultra/io/vi.c
@@ -17,7 +17,7 @@ void __osViInit(void) {
         __osViNext->modep = &osViModePalLan1;
     } else if (osTvType == OS_TV_MPAL) {
         __osViNext->modep = &osViModeMpalLan1;
-    } else {
+    } else { // OS_TV_NTSC or OS_TV_UNK28
         __osViNext->modep = &osViModeNtscLan1;
     }