diff --git a/include/PRinternal/macros.h b/include/PRinternal/macros.h
index 23d2b7d..1bdfc58 100644
--- a/include/PRinternal/macros.h
+++ b/include/PRinternal/macros.h
@@ -9,6 +9,8 @@
 
 #define UNUSED __attribute__((unused))
 
+#define FALLTHROUGH __attribute__((fallthrough))
+
 #ifndef __GNUC__
 #define __attribute__(x)
 #endif
diff --git a/src/audio/cseq.c b/src/audio/cseq.c
index 13f72eb..0209d7d 100644
--- a/src/audio/cseq.c
+++ b/src/audio/cseq.c
@@ -59,7 +59,7 @@ void alCSeqNew(ALCSeq* seq, u8* ptr) {
 void alCSeqNextEvent(ALCSeq* seq, ALEvent* evt) {
     u32 i;
     u32 firstTime = 0xFFFFFFFF;
-    u32 firstTrack;
+    u32 firstTrack = 0;
     u32 lastTicks = seq->lastDeltaTicks;
 
 #ifdef _DEBUG
diff --git a/src/audio/csplayer.c b/src/audio/csplayer.c
index 0f267a7..3b20674 100644
--- a/src/audio/csplayer.c
+++ b/src/audio/csplayer.c
@@ -43,6 +43,7 @@
 #include "seqp.h"
 #include "cseqp.h"
 #include "cseq.h"
+#include <PRinternal/macros.h>
 // TODO: this comes from a header
 #ident "$Revision: 1.17 $"
 static ALMicroTime __CSPVoiceHandler(void* node);
@@ -534,7 +535,7 @@ static void __CSPHandleMIDIMsg(ALCSPlayer* seqp, ALEvent* event) {
              * velocity (Should never happen with compact midi sequence,
              * but could happen with real time midi.)
              */
-
+            FALLTHROUGH;
         case (AL_MIDI_NoteOff):
             vstate = __lookupVoice((ALSeqPlayer*)seqp, key, chan);
             ALFlagFailIf(!vstate, seqp->debugFlags & NOTE_OFF_ERR_MASK, ERR_ALSEQP_OFF_VOICE);
diff --git a/src/audio/env.c b/src/audio/env.c
index b3e39b5..fe1ce1d 100644
--- a/src/audio/env.c
+++ b/src/audio/env.c
@@ -482,7 +482,7 @@ static s16 _getRate(f64 vol, f64 tgt, s32 count, u16* ratel) {
         }
     }
 
-    a *= (a *= (a *= a));
+    a = (a * a * a * a * a * a * a * a);
     s = (s16)a;
     *ratel = (s16)(0xffff * (a - (f32)s));
 
diff --git a/src/audio/load.c b/src/audio/load.c
index 9ae078e..1ece2d5 100644
--- a/src/audio/load.c
+++ b/src/audio/load.c
@@ -64,7 +64,7 @@ Acmd* alAdpcmPull(void* filter, s16* outp, s32 outCount, s32 sampleOffset, Acmd*
     inp = AL_DECODER_IN;
     aLoadADPCM(ptr++, f->bookSize, K0_TO_PHYS(f->table->waveInfo.adpcmWave.book->book));
 
-    looped = (outCount + f->sample > f->loop.end) && (f->loop.count != 0);
+    looped = ((u32)(outCount + f->sample) > f->loop.end) && (f->loop.count != 0);
     if (looped)
         nSam = f->loop.end - f->sample;
     else
@@ -121,13 +121,13 @@ Acmd* alAdpcmPull(void* filter, s16* outp, s32 outCount, s32 sampleOffset, Acmd*
              * -1 is loop forever - the loop count is not exact now
              * for small loops!
              */
-            if ((f->loop.count != -1) && (f->loop.count != 0))
+            if ((f->loop.count != 0xFFFFFFFF) && (f->loop.count != 0))
                 f->loop.count--;
 
             /*
              * What's left to compute.
              */
-            nSam = MIN(outCount, f->loop.end - f->loop.start);
+            nSam = MIN((u32)outCount, f->loop.end - f->loop.start);
             tsam = nSam - ADPCMFSIZE + f->lastsam;
             if (tsam < 0)
                 tsam = 0;
@@ -220,7 +220,7 @@ Acmd* alRaw16Pull(void* filter, s16* outp, s32 outCount, s32 sampleOffset, Acmd*
     if (outCount == 0)
         return ptr;
 
-    if ((outCount + f->sample > f->loop.end) && (f->loop.count != 0)) {
+    if (((u32)(outCount + f->sample) > f->loop.end) && (f->loop.count != 0)) {
 
         nSam = f->loop.end - f->sample;
         nbytes = nSam << 1;
@@ -254,13 +254,13 @@ Acmd* alRaw16Pull(void* filter, s16* outp, s32 outCount, s32 sampleOffset, Acmd*
             /*
              * -1 is loop forever
              */
-            if ((f->loop.count != -1) && (f->loop.count != 0))
+            if ((f->loop.count != 0xFFFFFFFF) && (f->loop.count != 0))
                 f->loop.count--;
 
             /*
              * What to compute.
              */
-            nSam = MIN(outCount, f->loop.end - f->loop.start);
+            nSam = MIN((u32)outCount, f->loop.end - f->loop.start);
             nbytes = nSam << 1;
 
             /*
@@ -418,6 +418,8 @@ s32 alLoadParam(void* filter, s32 paramID, void* param) {
         default:
             break;
     }
+
+    return 0;
 }
 
 Acmd* _decodeChunk(Acmd* ptr, ALLoadFilter* f, s32 tsam, s32 nbytes, s16 outp, s16 inp, u32 flags) {
diff --git a/src/audio/seq.c b/src/audio/seq.c
index 0e5b02f..3dfb7aa 100644
--- a/src/audio/seq.c
+++ b/src/audio/seq.c
@@ -240,8 +240,7 @@ void alSeqNewMarker(ALSeq* seq, ALSeqMarker* m, u32 ticks) {
                 lastTicks = seq->lastTicks;
                 break;
             }
-
-        } while (seq->lastTicks < ticks);
+        } while ((u32)seq->lastTicks < ticks);
 
         m->curPtr = lastPtr;
         m->lastStatus = lastStatus;
diff --git a/src/audio/seqplayer.c b/src/audio/seqplayer.c
index 22f58fb..dd39434 100644
--- a/src/audio/seqplayer.c
+++ b/src/audio/seqplayer.c
@@ -37,6 +37,7 @@
 #include <os_internal.h>
 #include <ultraerror.h>
 #include <assert.h>
+#include <PRinternal/macros.h>
 #include "seqp.h"
 #include "seq.h"
 
@@ -539,7 +540,7 @@ void __handleMIDIMsg(ALSeqPlayer* seqp, ALEvent* event) {
              * NOTE: intentional fall-through for note on with zero
              * velocity
              */
-
+            FALLTHROUGH;
         case (AL_MIDI_NoteOff):
             vstate = __lookupVoice(seqp, key, chan);
             ALFlagFailIf(!vstate, (seqp->debugFlags & NOTE_OFF_ERR_MASK), ERR_ALSEQP_OFF_VOICE);
diff --git a/src/audio/sndplayer.c b/src/audio/sndplayer.c
index c54d90d..276d4ef 100644
--- a/src/audio/sndplayer.c
+++ b/src/audio/sndplayer.c
@@ -39,7 +39,7 @@ void alSndpNew(ALSndPlayer* sndp, ALSndpConfig* c) {
     sState = (ALSoundState*)alHeapAlloc(c->heap, 1, c->maxSounds * sizeof(ALSoundState));
     sndp->sndState = sState;
 
-    for (i = 0; i < c->maxSounds; i++)
+    for (i = 0; i < (u32)c->maxSounds; i++)
         sState[i].sound = 0;
 
     /*
diff --git a/src/audio/synthesizer.c b/src/audio/synthesizer.c
index 65c868d..bc6714e 100644
--- a/src/audio/synthesizer.c
+++ b/src/audio/synthesizer.c
@@ -250,11 +250,8 @@ void __freeParam(ALParam* param) {
 
 void _collectPVoices(ALSynth* drvr) {
     ALLink* dl;
-    PVoice* pv;
 
     while ((dl = drvr->pLameList.next) != 0) {
-        pv = (PVoice*)dl;
-
         /* ### remove from mixer */
 
         alUnlink(dl);
diff --git a/src/error/kmcprintf.c b/src/error/kmcprintf.c
index 3d9f536..efe165f 100644
--- a/src/error/kmcprintf.c
+++ b/src/error/kmcprintf.c
@@ -227,17 +227,16 @@ static void kmcErrorHandler(s16 code, s16 numArgs, ...);
 OSErrorHandler __kmcErrorHandler = kmcErrorHandler;
 
 static void kmcErrorHandler(s16 code, s16 numArgs, ...) {
-    int ans;
     va_list ap;
-    char* fmt;
+    const char* fmt;
 
     fmt = __os_error_message[code];
     va_start(ap, numArgs);
 
     if (__kmc_pt_mode) {
-        ans = _Printf(kmc_proutSyncPrintf, NULL, fmt, ap);
+        _Printf(kmc_proutSyncPrintf, NULL, fmt, ap);
     } else {
-        ans = _Printf(proutSyncPrintf, NULL, fmt, ap);
+        _Printf(proutSyncPrintf, NULL, fmt, ap);
     }
 
     osSyncPrintf("\n");
diff --git a/src/gt/dumpturbo.c b/src/gt/dumpturbo.c
index 3fcfbe7..08893f1 100644
--- a/src/gt/dumpturbo.c
+++ b/src/gt/dumpturbo.c
@@ -28,7 +28,7 @@ static u32 textures[TX_MAX] ALIGNED(0x8);
 static u32 numtextures;
 
 #define UNSEG_ADDR(sa)                                                                                                 \
-    ((u32*)(((globp) ? (((int)(sa) & 0x00ffffff) + globp->sp.segBases[(int)(sa) >> 24]) : (int)(sa)) | 0x80000000))
+    ((u32*)(((globp) ? (((u32)(sa) & 0x00ffffff) + globp->sp.segBases[(u32)(sa) >> 24]) : (u32)(sa)) | 0x80000000))
 #define PHYS(a)   ((int)((int)(a) & 0x7fffffff))
 #define UNPHYS(a) ((u32*)((int)(a) | 0x80000000))
 
@@ -38,7 +38,7 @@ static u32 numtextures;
 
 #define UCODE_SIZE_MAX (4096 * 1)
 void gtDumpTurbo(OSTask* tp, u8 flags) {
-    int i;
+    u32 i;
     gtGfx* gtlistp;
     gtGlobState* globp = 0;
     gtState* statep;
@@ -53,17 +53,17 @@ void gtDumpTurbo(OSTask* tp, u8 flags) {
 
 #if 1
     PRINTF("? %08x\n", PHYS(tp->t.ucode_boot));
-    for (i = (int)tp->t.ucode_boot; i < (int)tp->t.ucode_boot + tp->t.ucode_boot_size; i += 4) {
+    for (i = (u32)tp->t.ucode_boot; i < (u32)(tp->t.ucode_boot + tp->t.ucode_boot_size); i += 4) {
         PRINTF("|%08x\n", (int)*((u32*)i));
     }
 
     PRINTF("? %08x\n", PHYS(tp->t.ucode));
-    for (i = (int)tp->t.ucode; i < (int)tp->t.ucode + UCODE_SIZE_MAX; i += 4) {
+    for (i = (u32)tp->t.ucode; i < (u32)(tp->t.ucode + UCODE_SIZE_MAX); i += 4) {
         PRINTF("|%08x\n", (int)*((u32*)i));
     }
 
     PRINTF("? %08x\n", PHYS(tp->t.ucode_data));
-    for (i = (int)tp->t.ucode_data; i < (int)tp->t.ucode_data + tp->t.ucode_data_size; i += 4) {
+    for (i = (u32)tp->t.ucode_data; i < (u32)(tp->t.ucode_data + tp->t.ucode_data_size); i += 4) {
         PRINTF("|%08x\n", (int)*((u32*)i));
     }
 
diff --git a/src/gt/gt.c b/src/gt/gt.c
index fc32ae6..b992a84 100644
--- a/src/gt/gt.c
+++ b/src/gt/gt.c
@@ -36,7 +36,7 @@
  * Set the cached RDP othermode word in the gt state structure.
  */
 void gtStateSetOthermode(Gfx* om, gtStateOthermode_t mode, int data) {
-    int shift, length;
+    int shift = 0, length = 0;
     u32 mask;
 
     if (mode == GT_CLEAR) { /* special case */
diff --git a/src/gu/cosf.c b/src/gu/cosf.c
index 2ee6ba4..0538c7e 100644
--- a/src/gu/cosf.c
+++ b/src/gu/cosf.c
@@ -37,15 +37,15 @@
 /* coefficients for polynomial approximation of cos on +/- pi/2 */
 
 static const du P[] = {
-    { 0x3ff00000, 0x00000000 }, { 0xbfc55554, 0xbc83656d }, { 0x3f8110ed, 0x3804c2a0 },
-    { 0xbf29f6ff, 0xeea56814 }, { 0x3ec5dbdf, 0x0e314bfe },
+    { { 0x3ff00000, 0x00000000 } }, { { 0xbfc55554, 0xbc83656d } }, { { 0x3f8110ed, 0x3804c2a0 } },
+    { { 0xbf29f6ff, 0xeea56814 } }, { { 0x3ec5dbdf, 0x0e314bfe } },
 };
 
-static const du rpi = { 0x3fd45f30, 0x6dc9c883 };
+static const du rpi = { { 0x3fd45f30, 0x6dc9c883 } };
 
-static const du pihi = { 0x400921fb, 0x50000000 };
+static const du pihi = { { 0x400921fb, 0x50000000 } };
 
-static const du pilo = { 0x3e6110b4, 0x611a6263 };
+static const du pilo = { { 0x3e6110b4, 0x611a6263 } };
 
 static const fu zero = { 0x00000000 };
 
diff --git a/src/gu/guloadtile_bug.c b/src/gu/guloadtile_bug.c
index eb12375..44ed627 100644
--- a/src/gu/guloadtile_bug.c
+++ b/src/gu/guloadtile_bug.c
@@ -30,12 +30,11 @@ void guDPLoadTextureTile(Gfx* temp, void* timg, int texl_fmt, int texl_size, int
                          int shiftt) {
     int line;
     int tile_width, tile_height; /*
-
-                                                                  * in texels
-                                                                  */
+                                  * in texels
+                                  */
     int dxt;
-    int sizeb;
-    int lineb;
+    int sizeb = 0;
+    int lineb = 0;
     int line_size;     /*
 
                                                 * in 64-bit words
@@ -140,7 +139,6 @@ void guDPLoadTextureTile_4b(Gfx* temp, void* timg, int texl_fmt, int img_width,
     int line;
     int tile_width, tile_height;
     int dxt;
-    int sizeb;
     int lineb;
     int line_size;
     int count;
@@ -150,7 +148,6 @@ void guDPLoadTextureTile_4b(Gfx* temp, void* timg, int texl_fmt, int img_width,
 
     tile_width = (lrs - uls + 1) >> 1;
     tile_height = lrt - ult + 1;
-    sizeb = G_IM_SIZ_8b_BYTES;
     lineb = G_IM_SIZ_8b_LINE_BYTES;
     line_size = ((tile_width * lineb) + 7) >> 3;
     dxt = CALC_DXT_4b(tile_width);
diff --git a/src/gu/loadtextureblockmipmap.c b/src/gu/loadtextureblockmipmap.c
index c6215f3..11bbdba 100644
--- a/src/gu/loadtextureblockmipmap.c
+++ b/src/gu/loadtextureblockmipmap.c
@@ -43,7 +43,7 @@ struct Tile {
 
 /* tram mipmaps */
 static struct Tile mipmap[MM_MAX_LEVEL + 1] ALIGNED(0x8);
-static struct texelSizeParams sizeParams[4] = { 16, 3, 1, 0, 8, 2, 2, 1, 4, 1, 4, 2, 2, 0, 8, 3 };
+static struct texelSizeParams sizeParams[4] = { { 16, 3, 1, 0 }, { 8, 2, 2, 1 }, { 4, 1, 4, 2 }, { 2, 0, 8, 3 } };
 
 static int max_mipmap;
 static unsigned char* tram;
@@ -493,7 +493,7 @@ int guLoadTextureBlockMipMap(Gfx** glistp, unsigned char* tbuf, Image* im, unsig
     /*
      * Add entries for texture loading and rendering in DL
      */
-    stuffDisplayList(glistp, im, tbuf, startTile, pal, cms, cmt, masks, maskt, shifts, shiftt);
+    stuffDisplayList(glistp, im, (char*)tbuf, startTile, pal, cms, cmt, masks, maskt, shifts, shiftt);
 
     return errNo;
 } /* end guLoadTextureBlockMipMap */
@@ -532,7 +532,7 @@ static void stuffDisplayList(Gfx** glistp, Image* im, char* tbuf, unsigned char
                              unsigned char shifts, unsigned char shiftt) {
     int tile;
     int Smask, Tmask;
-    int Sshift, Tshift;
+    int Sshift = 0, Tshift = 0;
 
     /*
      * set LOADTILE for loading texture
diff --git a/src/gu/sinf.c b/src/gu/sinf.c
index e127821..910db00 100644
--- a/src/gu/sinf.c
+++ b/src/gu/sinf.c
@@ -37,15 +37,15 @@
 /* coefficients for polynomial approximation of sin on +/- pi/2 */
 
 static const du P[] = {
-    { 0x3ff00000, 0x00000000 }, { 0xbfc55554, 0xbc83656d }, { 0x3f8110ed, 0x3804c2a0 },
-    { 0xbf29f6ff, 0xeea56814 }, { 0x3ec5dbdf, 0x0e314bfe },
+    { { 0x3ff00000, 0x00000000 } }, { { 0xbfc55554, 0xbc83656d } }, { { 0x3f8110ed, 0x3804c2a0 } },
+    { { 0xbf29f6ff, 0xeea56814 } }, { { 0x3ec5dbdf, 0x0e314bfe } },
 };
 
-static const du rpi = { 0x3fd45f30, 0x6dc9c883 };
+static const du rpi = { { 0x3fd45f30, 0x6dc9c883 } };
 
-static const du pihi = { 0x400921fb, 0x50000000 };
+static const du pihi = { { 0x400921fb, 0x50000000 } };
 
-static const du pilo = { 0x3e6110b4, 0x611a6263 };
+static const du pilo = { { 0x3e6110b4, 0x611a6263 } };
 
 static const fu zero = { 0x00000000 };
 
diff --git a/src/gu/us2dex_emu.c b/src/gu/us2dex_emu.c
index 34e701e..89e3156 100644
--- a/src/gu/us2dex_emu.c
+++ b/src/gu/us2dex_emu.c
@@ -62,9 +62,9 @@ static void tmemLoad_B(Gfx** pkt, u32 imagePtr, s16 loadLines, s16 tmemSH) {
     (*pkt)->words.w0 = (G_LOADTILE << 24) | 0x000000;
     /* addition 99/5/31(Y) */
     if (bgflg == 3)
-        (*pkt)->words.w1 = 0x07000000 | (tmemSH - 1) << 16;
+        (*pkt)->words.w1 = 0x07000000 | ((tmemSH - 1) << 16);
     else
-        (*pkt)->words.w1 = 0x07000000 | (tmemSH - 1) << 16 | (loadLines << 2) - 1;
+        (*pkt)->words.w1 = 0x07000000 | ((tmemSH - 1) << 16) | ((loadLines << 2) - 1);
     (*pkt)++;
 }
 
@@ -123,7 +123,7 @@ static void tmemLoad(Gfx** pkt, u32* imagePtr, s16* imageRemain, s16 drawLines,
             imagePtr1A = (*imagePtr) + iLoadable * imageSrcWsize;
             imagePtr1B = imageTop;
             SubSliceY1 = iLoadable;
-            if (SubSliceL1 = iLoadable & 1) {
+            if ((SubSliceL1 = iLoadable & 1)) {
                 imagePtr1A -= imageSrcWsize;
                 imagePtr1B -= imageSrcWsize;
                 imagePtr1B = imageTopSeg | (imagePtr1B & 0x00ffffff); /*Segment countermeasure */
@@ -477,10 +477,10 @@ void guS2DEmuBgRect1Cyc(Gfx** pkt, uObjBg* bg) {
 	(*pkt)->words.w0 = (imageS<<16) | imageT;
 	(*pkt)->words.w1 = (scaleW<<16) | scaleH;
 #else /* At RSP command creation time */
-                    (*pkt)->words.w0 = (G_RDPHALF_1 << 24);
+                    (*pkt)->words.w0 = ((u8)G_RDPHALF_1 << 24);
                     (*pkt)->words.w1 = (imageS << 16) | imageT;
                     (*pkt)++;
-                    (*pkt)->words.w0 = (G_RDPHALF_2 << 24);
+                    (*pkt)->words.w0 = ((u8)G_RDPHALF_2 << 24);
                     (*pkt)->words.w1 = (scaleW << 16) | scaleH;
 #endif
                     (*pkt)++;
diff --git a/src/io/aisetnextbuf.c b/src/io/aisetnextbuf.c
index 9ef8a26..3aa7f3d 100644
--- a/src/io/aisetnextbuf.c
+++ b/src/io/aisetnextbuf.c
@@ -19,7 +19,7 @@
  */
 s32 osAiSetNextBuffer(void* bufPtr, u32 size) {
     static u8 hdwrBugFlag = FALSE;
-    char* bptr;
+    u8* bptr;
 
     if (__osAiDeviceBusy()) {
         return -1;
diff --git a/src/io/conteepread.c b/src/io/conteepread.c
index a7d6296..d48b436 100644
--- a/src/io/conteepread.c
+++ b/src/io/conteepread.c
@@ -28,12 +28,7 @@ s32 osEepromRead(OSMesgQueue* mq, u8 address, u8* buffer) {
                 }
                 break;
             case CONT_EEPROM | CONT_EEP16K:
-                if (address >= EEP16K_MAXBLOCKS) {
-                    // not technically possible
-                    ret = CONT_RANGE_ERROR;
-                } else {
-                    __osEepromRead16K = 1;
-                }
+                __osEepromRead16K = 1;
                 break;
             default:
                 ret = CONT_NO_RESPONSE_ERROR;
diff --git a/src/io/conteepwrite.c b/src/io/conteepwrite.c
index b75fae0..73086e7 100644
--- a/src/io/conteepwrite.c
+++ b/src/io/conteepwrite.c
@@ -26,10 +26,7 @@ s32 osEepromWrite(OSMesgQueue* mq, u8 address, u8* buffer) {
                 }
                 break;
             case CONT_EEPROM | CONT_EEP16K:
-                if (address >= EEP16K_MAXBLOCKS) {
-                    // not technically possible
-                    ret = CONT_RANGE_ERROR;
-                } else if (__osEepromRead16K) {
+                if (__osEepromRead16K) {
                     __osEepromRead16K = 0;
                     __osSiRelAccess();
                     osEepromRead(mq, (address ^ 1), temp);
@@ -99,7 +96,7 @@ s32 __osEepStatus(OSMesgQueue* mq, OSContStatus* data) {
     u8* ptr = (u8*)__osEepPifRam.ramarray;
     __OSContRequesFormat requestformat;
 
-    for (i = 0; i < ARRLEN(__osEepPifRam.ramarray) + 1; i++) {
+    for (i = 0; i < ARRLEN(__osEepPifRam.ramarray); i++) {
         __osEepPifRam.ramarray[i] = 0;
     }
 
diff --git a/src/io/contramread.c b/src/io/contramread.c
index dbefd03..b603a8c 100644
--- a/src/io/contramread.c
+++ b/src/io/contramread.c
@@ -19,7 +19,7 @@ s32 __osContRamRead(OSMesgQueue* mq, int channel, u16 address, u8* buffer) {
     do {
         ptr = (u8*)&__osPfsPifRam;
 
-        if (__osContLastCmd != CONT_CMD_READ_PAK || (u32)__osPfsLastChannel != channel) {
+        if (__osContLastCmd != CONT_CMD_READ_PAK || __osPfsLastChannel != channel) {
             __osContLastCmd = CONT_CMD_READ_PAK;
             __osPfsLastChannel = channel;
 
diff --git a/src/io/contramwrite.c b/src/io/contramwrite.c
index 8a86126..3e9442a 100644
--- a/src/io/contramwrite.c
+++ b/src/io/contramwrite.c
@@ -24,7 +24,7 @@ s32 __osContRamWrite(OSMesgQueue* mq, int channel, u16 address, u8* buffer, int
     do {
         ptr = (u8*)__osPfsPifRam.ramarray;
 
-        if (__osContLastCmd != CONT_CMD_WRITE_PAK || (u32)__osPfsLastChannel != channel) {
+        if (__osContLastCmd != CONT_CMD_WRITE_PAK || __osPfsLastChannel != channel) {
             __osContLastCmd = CONT_CMD_WRITE_PAK;
             __osPfsLastChannel = channel;
 
diff --git a/src/libc/xldtob.c b/src/libc/xldtob.c
index c2703db..6fd292e 100644
--- a/src/libc/xldtob.c
+++ b/src/libc/xldtob.c
@@ -10,7 +10,7 @@
 #define BUFF_LEN 0x20
 
 static short _Ldunscale(short* pex, ldouble* px);
-static void _Genld(_Pft* px, char code, unsigned char* p, short nsig, short xexp);
+static void _Genld(_Pft* px, char code, char* p, short nsig, short xexp);
 
 static const ldouble pows[] = { 10e0L, 10e1L, 10e3L, 10e7L, 10e15L, 10e31L, 10e63L, 10e127L, 10e255L };
 
@@ -179,14 +179,14 @@ short _Ldunscale(short* pex, ldouble* px) {
     }
 }
 
-void _Genld(_Pft* px, char code, unsigned char* p, short nsig, short xexp) {
+void _Genld(_Pft* px, char code, char* p, short nsig, short xexp) {
     const unsigned char point = '.';
 
     if (nsig <= 0) {
         nsig = 1, p = "0";
     }
 
-    if (code == 'f' || (code == 'g' || code == 'G') && xexp >= -4 && xexp < px->prec) {
+    if (code == 'f' || ((code == 'g' || code == 'G') && xexp >= -4 && xexp < px->prec)) {
         xexp++;
         if (code != 'f') {
             if (((px->flags & 8) == 0) && nsig < px->prec) {
diff --git a/src/libc/xprintf.c b/src/libc/xprintf.c
index 219fc68..b074ce9 100644
--- a/src/libc/xprintf.c
+++ b/src/libc/xprintf.c
@@ -105,7 +105,7 @@ int _Printf(void* pfn(void*, const char*, size_t), void* arg, const char* fmt, v
             if (!(x.flags & FLAGS_MINUS)) {
                 int i, j;
                 if (0 < (x.width)) {
-                    i, j = x.width;
+                    j = x.width;
                     for (; 0 < j; j -= i) {
                         i = MAX_PAD < (unsigned int)j ? (int)MAX_PAD : j;
                         PUT(spaces, i);
diff --git a/src/libc/xstdio.h b/src/libc/xstdio.h
index b9f5e83..3b0ac13 100644
--- a/src/libc/xstdio.h
+++ b/src/libc/xstdio.h
@@ -15,7 +15,7 @@ typedef struct {
         /* 0x0 */ long long ll;
         /* 0x0 */ ldouble ld;
     } v;
-    /* 0x8 */ unsigned char* s;
+    /* 0x8 */ char* s;
     /* 0xC */ int n0;
     /* 0x10 */ int nz0;
     /* 0x14 */ int n1;
diff --git a/src/os/settimer.c b/src/os/settimer.c
index da186cd..d1fbf99 100644
--- a/src/os/settimer.c
+++ b/src/os/settimer.c
@@ -39,7 +39,7 @@ int osSetTimer(OSTimer* t, OSTime countdown, OSTime interval, OSMesgQueue* mq, O
         }
     }
 
-    time = __osInsertTimer(t);
+    __osInsertTimer(t);
     __osSetTimerIntr(__osTimerList->next->value);
     __osRestoreInt(saveMask);
 
diff --git a/src/os/timerintr.c b/src/os/timerintr.c
index 9c08f6a..3b7adeb 100644
--- a/src/os/timerintr.c
+++ b/src/os/timerintr.c
@@ -87,9 +87,8 @@ void __osTimerInterrupt(void) {
                 __osProfileOverflowBin++;
             }
         }
-#endif
-
     __ProfDone:
+#endif
 
         if (t->interval != 0) {
             t->value = t->interval;
diff --git a/src/rg/malloc.c b/src/rg/malloc.c
index e397420..3201ab4 100644
--- a/src/rg/malloc.c
+++ b/src/rg/malloc.c
@@ -8,7 +8,7 @@
 
 void* osMalloc(void* region) {
     register OSRegion* rp = region;
-    char* addr;
+    u8* addr;
 
 #ifdef _DEBUG
     assert(rp != NULL);
diff --git a/src/rg/region.c b/src/rg/region.c
index 7d08c8d..9801567 100644
--- a/src/rg/region.c
+++ b/src/rg/region.c
@@ -9,7 +9,7 @@
 void* osCreateRegion(void* startAddress, u32 length, u32 bufferSize, u32 alignSize) {
     register OSRegion* rp;
     register int i;
-    register char* addr;
+    register u8* addr;
 
     assert(startAddress != NULL);
 
diff --git a/src/sched/sched.c b/src/sched/sched.c
index 53b3032..a3a5e01 100644
--- a/src/sched/sched.c
+++ b/src/sched/sched.c
@@ -351,7 +351,6 @@ OSScTask* __scTaskReady(OSScTask* t) {
  * client if it is.
  */
 s32 __scTaskComplete(OSSched* sc, OSScTask* t) {
-    int rv;
     static int firsttime = 1;
 
     if ((t->state & OS_SC_RCP_MASK) == 0) { /* none of the needs bits set */
@@ -365,7 +364,7 @@ s32 __scTaskComplete(OSSched* sc, OSScTask* t) {
 #ifdef SC_LOGGING
         osLogEvent(l, 504, 1, t);
 #endif
-        rv = osSendMesg(t->msgQ, t->msg, OS_MESG_BLOCK);
+        osSendMesg(t->msgQ, t->msg, OS_MESG_BLOCK);
 
         if (t->list.t.type == M_GFXTASK) {
             if ((t->flags & OS_SC_SWAPBUFFER) && (t->flags & OS_SC_LAST_TASK)) {
@@ -424,8 +423,6 @@ void __scAppendList(OSSched* sc, OSScTask* t) {
  *
  */
 void __scExec(OSSched* sc, OSScTask* sp, OSScTask* dp) {
-    int rv;
-
 #ifdef SC_LOGGING
     osLogEvent(l, 511, 2, sp, dp);
 #endif
@@ -454,13 +451,11 @@ void __scExec(OSSched* sc, OSScTask* sp, OSScTask* dp) {
 #ifdef SC_LOGGING
         osLogEvent(l, 523, 3, dp, dp->list.t.output_buff, (u32)*dp->list.t.output_buff_size);
 #endif
-        rv = osDpSetNextBuffer(dp->list.t.output_buff, *dp->list.t.output_buff_size);
+        assert(osDpSetNextBuffer(dp->list.t.output_buff, *dp->list.t.output_buff_size) == 0);
 
         dp_busy = 1;
         dpCount = 0;
 
-        assert(rv == 0);
-
         sc->curRDPTask = dp;
     }
 }
@@ -539,7 +534,7 @@ s32 __scSchedule(OSSched* sc, OSScTask** sp, OSScTask** dp, s32 availRCP) {
                                 *dp = gfx;
                                 avail &= ~OS_SC_DP;
 
-                                if (avail & OS_SC_DP == 0)
+                                if ((avail & OS_SC_DP) == 0)
                                     assert(sc->curRDPTask == gfx);
                             }
 
diff --git a/src/voice/voicecheckword.c b/src/voice/voicecheckword.c
index 298bd24..017c98e 100644
--- a/src/voice/voicecheckword.c
+++ b/src/voice/voicecheckword.c
@@ -11,7 +11,7 @@
 s32 osVoiceCheckWord(u8* word) {
     s32 k;
     s32 ret = 0;
-    u16 sjis;
+    u16 sjis = '\0';
     u16 old = '\0';
 
     for (k = 0; word[k] != 0; k += 2) {
diff --git a/src/voice/voicecontread2.c b/src/voice/voicecontread2.c
index 66ef5a4..b6da2ff 100644
--- a/src/voice/voicecontread2.c
+++ b/src/voice/voicecontread2.c
@@ -25,7 +25,7 @@ s32 __osVoiceContRead2(OSMesgQueue* mq, int channel, u16 address, u8* buffer) {
 
         ptr = (u8*)&__osPfsPifRam.ramarray;
 
-        if ((__osContLastCmd != CONT_CMD_READ2_VOICE) || ((u32)__osPfsLastChannel != channel)) {
+        if ((__osContLastCmd != CONT_CMD_READ2_VOICE) || (__osPfsLastChannel != channel)) {
             __osContLastCmd = CONT_CMD_READ2_VOICE;
             __osPfsLastChannel = channel;
 
diff --git a/src/voice/voicecontread36.c b/src/voice/voicecontread36.c
index 4be3c48..cef5c91 100644
--- a/src/voice/voicecontread36.c
+++ b/src/voice/voicecontread36.c
@@ -25,7 +25,7 @@ s32 __osVoiceContRead36(OSMesgQueue* mq, int channel, u16 address, u8* buffer) {
 
         ptr = (u8*)&__osPfsPifRam.ramarray;
 
-        if ((__osContLastCmd != CONT_CMD_READ36_VOICE) || ((u32)__osPfsLastChannel != channel)) {
+        if ((__osContLastCmd != CONT_CMD_READ36_VOICE) || (__osPfsLastChannel != channel)) {
             __osContLastCmd = CONT_CMD_READ36_VOICE;
             __osPfsLastChannel = channel;
 
diff --git a/src/voice/voicecontwrite20.c b/src/voice/voicecontwrite20.c
index 7b96382..e814cf5 100644
--- a/src/voice/voicecontwrite20.c
+++ b/src/voice/voicecontwrite20.c
@@ -26,7 +26,7 @@ s32 __osVoiceContWrite20(OSMesgQueue* mq, int channel, u16 address, u8* buffer)
 
         ptr = (u8*)&__osPfsPifRam;
 
-        if ((__osContLastCmd != CONT_CMD_WRITE20_VOICE) || ((u32)__osPfsLastChannel != channel)) {
+        if ((__osContLastCmd != CONT_CMD_WRITE20_VOICE) || (__osPfsLastChannel != channel)) {
             __osContLastCmd = CONT_CMD_WRITE20_VOICE;
             __osPfsLastChannel = channel;
 
diff --git a/src/voice/voicecontwrite4.c b/src/voice/voicecontwrite4.c
index 8d212fc..710c337 100644
--- a/src/voice/voicecontwrite4.c
+++ b/src/voice/voicecontwrite4.c
@@ -26,7 +26,7 @@ s32 __osVoiceContWrite4(OSMesgQueue* mq, int channel, u16 address, u8* buffer) {
 
         ptr = (u8*)&__osPfsPifRam;
 
-        if ((__osContLastCmd != CONT_CMD_WRITE4_VOICE) || ((u32)__osPfsLastChannel != channel)) {
+        if ((__osContLastCmd != CONT_CMD_WRITE4_VOICE) || (__osPfsLastChannel != channel)) {
             __osContLastCmd = CONT_CMD_WRITE4_VOICE;
             __osPfsLastChannel = channel;
 
diff --git a/src/voice/voicegetreaddata.c b/src/voice/voicegetreaddata.c
index c4f8f1b..15efae3 100644
--- a/src/voice/voicegetreaddata.c
+++ b/src/voice/voicegetreaddata.c
@@ -6,6 +6,7 @@
 
 #include "PR/os_internal.h"
 #include "PRinternal/controller.h"
+#include "PRinternal/macros.h"
 #include "PR/os_voice.h"
 #include "voiceinternal.h"
 
@@ -32,6 +33,7 @@ s32 osVoiceGetReadData(OSVoiceHandle* hd, OSVoiceData* micdata) {
             if ((c != 0) && (c != 7)) {
                 return CONT_ERR_NOT_READY;
             }
+            FALLTHROUGH;
         case 2:
             hd->__mode = 2;
 
@@ -43,7 +45,7 @@ s32 osVoiceGetReadData(OSVoiceHandle* hd, OSVoiceData* micdata) {
 
             *(u32*)temp = 0x600;
             ERRCK(__osVoiceContWrite4(hd->__mq, hd->__channel, 0, temp));
-
+            FALLTHROUGH;
         case 3:
             hd->__mode = 3;
 
@@ -75,6 +77,7 @@ s32 osVoiceGetReadData(OSVoiceHandle* hd, OSVoiceData* micdata) {
             if ((c == 0) || (hd->cmd_status == 0)) {
                 break;
             }
+            FALLTHROUGH;
         case 4:
             hd->__mode = 4;
 
diff --git a/src/voice/voicestopreaddata.c b/src/voice/voicestopreaddata.c
index 53f5061..1b137a4 100644
--- a/src/voice/voicestopreaddata.c
+++ b/src/voice/voicestopreaddata.c
@@ -12,7 +12,7 @@
 
 s32 osVoiceStopReadData(OSVoiceHandle* hd) {
     s32 ret;
-    s32 i;
+    s32 i = 0;
     u8 stat;
     u8 temp[4];
 
@@ -48,7 +48,7 @@ s32 osVoiceStopReadData(OSVoiceHandle* hd) {
         } while ((ret == CONT_ERR_VOICE_NO_RESPONSE) && (i < 20));
     }
     if (i >= 20) {
-        ret == CONT_ERR_VOICE_NO_RESPONSE;
+        ret = CONT_ERR_VOICE_NO_RESPONSE;
     }
 
     return ret;