--- a/src/in_gsf/vbam/apu/Blip_Buffer.cpp
+++ b/src/in_gsf/vbam/apu/Blip_Buffer.cpp
@@ -264,7 +264,7 @@
 		fimpulse[blip_res + half_size + i] = fimpulse[blip_res + half_size - 1 - i];
 
 	// starts at 0
-	std::fill(&fimpulse[0], &fimpulse[blip_res], 0.0f);
+	std::fill_n(&fimpulse[0], blip_res, 0.0f);
 
 	// find rescale factor
 	double total = std::accumulate(&fimpulse[blip_res], &fimpulse[blip_res + half_size], 0.0);

--- a/src/in_gsf/vbam/apu/Gb_Apu.cpp
+++ b/src/in_gsf/vbam/apu/Gb_Apu.cpp
@@ -83,7 +83,7 @@
 
 void Gb_Apu::reset_regs()
 {
-	std::fill(&this->regs[0], &this->regs[0x20], 0);
+	std::fill_n(&this->regs[0], 0x20, 0);
 
 	this->square1.reset();
 	this->square2.reset();

--- a/src/in_gsf/vbam/gba/GBA.cpp
+++ b/src/in_gsf/vbam/gba/GBA.cpp
@@ -1505,7 +1505,7 @@
 		cpuBitsSet[i] = count;
 	}
 
-	std::fill(&ioReadable[0], &ioReadable[0x304], true);
+	std::fill_n(&ioReadable[0], 0x304, true);
 	std::fill(&ioReadable[0x10], &ioReadable[0x48], false);
 	std::fill(&ioReadable[0x4c], &ioReadable[0x50], false);
 	std::fill(&ioReadable[0x54], &ioReadable[0x60], false);

--- a/src/in_ncsf/SSEQPlayer/Channel.h
+++ b/src/in_ncsf/SSEQPlayer/Channel.h
@@ -102,11 +102,11 @@
 
 	RingBuffer() : bufferPos(N / 2), getPos(N / 2)
 	{
-		std::fill(&this->buffer[0], &this->buffer[N * 2], 0);
+		std::fill_n(&this->buffer[0], N * 2, 0);
 	}
 	void Clear()
 	{
-		std::fill(&this->buffer[0], &this->buffer[N * 2], 0);
+		std::fill_n(&this->buffer[0], N * 2, 0);
 		this->bufferPos = this->getPos = N / 2;
 	}
 	void PushSample(int16_t sample)
@@ -125,11 +125,11 @@
 		if (this->bufferPos + size > N * 3 / 2)
 		{
 			size_t free = N * 3 / 2 - this->bufferPos;
-			std::copy(&samples[0], &samples[free], &this->buffer[this->bufferPos]);
+			std::copy_n(&samples[0], free, &this->buffer[this->bufferPos]);
 			std::copy(&samples[free], &samples[size], &this->buffer[N / 2]);
 		}
 		else
-			std::copy(&samples[0], &samples[size], &this->buffer[this->bufferPos]);
+			std::copy_n(&samples[0], size, &this->buffer[this->bufferPos]);
 		size_t rightFree = this->bufferPos < N ? N - this->bufferPos : 0;
 		if (rightFree < size)
 		{
@@ -137,18 +137,18 @@
 			{
 				size_t leftStart = this->bufferPos - N;
 				size_t leftSize = std::min(N / 2 - leftStart, size);
-				std::copy(&samples[0], &samples[leftSize], &this->buffer[leftStart]);
+				std::copy_n(&samples[0], leftSize, &this->buffer[leftStart]);
 				if (leftSize < size)
 					std::copy(&samples[leftSize], &samples[size], &this->buffer[N * 3 / 2]);
 			}
 			else
 			{
-				std::copy(&samples[0], &samples[rightFree], &this->buffer[this->bufferPos + N]);
+				std::copy_n(&samples[0], rightFree, &this->buffer[this->bufferPos + N]);
 				std::copy(&samples[rightFree], &samples[size], &this->buffer[0]);
 			}
 		}
 		else
-			std::copy(&samples[0], &samples[size], &this->buffer[this->bufferPos + N]);
+			std::copy_n(&samples[0], size, &this->buffer[this->bufferPos + N]);
 		this->bufferPos += size;
 		if (this->bufferPos >= N * 3 / 2)
 			this->bufferPos -= N;

--- a/src/in_xsf_framework/XSFPlayer.cpp
+++ b/src/in_xsf_framework/XSFPlayer.cpp
@@ -66,12 +66,12 @@
 		if (this->uses32BitSamplesClampedTo16Bit)
 		{
 			auto trueBufLong = reinterpret_cast<int32_t *>(&trueBuffer[0]);
-			std::copy(&trueBufLong[0], &trueBufLong[bufsize << 1], &bufLong[0]);
+			std::copy_n(&trueBufLong[0], bufsize << 1, &bufLong[0]);
 		}
 		else
 		{
 			auto trueBufShort = reinterpret_cast<int16_t *>(&trueBuffer[0]);
-			std::copy(&trueBufShort[0], &trueBufShort[bufsize << 1], &bufLong[0]);
+			std::copy_n(&trueBufShort[0], bufsize << 1, &bufLong[0]);
 		}
 		if (detectSilence || skipSilenceOnStartSec)
 		{
@@ -117,7 +117,7 @@
 				{
 					auto tmpBuf = std::vector<int32_t>((bufsize - skipOffset) << 1);
 					std::copy(&bufLong[(offset + skipOffset) << 1], &bufLong[bufsize << 1], &tmpBuf[0]);
-					std::copy(&tmpBuf[0], &tmpBuf[(bufsize - skipOffset) << 1], &bufLong[offset << 1]);
+					std::copy_n(&tmpBuf[0], (bufsize - skipOffset) << 1, &bufLong[offset << 1]);
 					pos += skipOffset;
 				}
 				else
@@ -131,12 +131,12 @@
 			if (this->uses32BitSamplesClampedTo16Bit)
 			{
 				auto trueBufLong = reinterpret_cast<int32_t *>(&trueBuffer[0]);
-				std::copy(&bufLong[0], &bufLong[bufsize << 1], &trueBufLong[0]);
+				std::copy_n(&bufLong[0], bufsize << 1, &trueBufLong[0]);
 			}
 			else
 			{
 				auto trueBufShort = reinterpret_cast<int16_t *>(&trueBuffer[0]);
-				std::copy(&bufLong[0], &bufLong[bufsize << 1], &trueBufShort[0]);
+				std::copy_n(&bufLong[0], bufsize << 1, &trueBufShort[0]);
 			}
 		}
 	}
@@ -188,7 +188,7 @@
 	else
 	{
 		auto trueBufShort = reinterpret_cast<int16_t *>(&trueBuffer[0]);
-		std::copy(&bufLong[0], &bufLong[bufsize << 1], &trueBufShort[0]);
+		std::copy_n(&bufLong[0], bufsize << 1, &trueBufShort[0]);
 		std::copy(&trueBuffer[0], &trueBuffer[bufsize << 2], &buf[0]);
 	}