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Improved scrolling and added better memcpy/memmove functions written in assembly.

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This commit is contained in:
Patrick 2024-01-16 13:16:03 +01:00
parent 6ec9e0d320
commit c745c2d2d3
4 changed files with 71 additions and 25 deletions
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4
targets/_any/include/string.h
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@ -11,8 +11,8 @@
BA_EXTERN_C_BEGIN
BA_CXX_NODISCARD int memcmp(const void* lhs, const void* rhs, size_t count) BA_CXX_NOEXCEPT;
void memcpy(void* dest, const void* src, size_t count) BA_CXX_NOEXCEPT;
void memmove(void* dest, const void* src, size_t count) BA_CXX_NOEXCEPT;
void* memcpy(void* dest, const void* src, size_t count) BA_CXX_NOEXCEPT;
void* memmove(void* dest, const void* src, size_t count) BA_CXX_NOEXCEPT;
void* memset(void* dest, int value, size_t count) BA_CXX_NOEXCEPT;
BA_CXX_NODISCARD size_t strlen(const char* str) BA_CXX_NOEXCEPT;

8
targets/_any/src/cstdlib/string.cpp
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@ -20,16 +20,16 @@ int memcmp(const void* lhs, const void* rhs, size_t count) noexcept
}
#if !defined(__x86_64__)
void memcpy(void* dest, const void* src, size_t count) noexcept
void* memcpy(void* dest, const void* src, size_t count) noexcept
{
for (size_t pos = 0; pos < count; ++pos)
{
*(static_cast<uint8_t*>(dest) + pos) = *(static_cast<const uint8_t*>(src) + pos);
}
return dest;
}
#endif
void memmove(void* dest, const void* src, size_t count) noexcept
void* memmove(void* dest, const void* src, size_t count) noexcept
{
if (dest < src)
{
@ -45,7 +45,9 @@ void memmove(void* dest, const void* src, size_t count) noexcept
*(static_cast<uint8_t*>(dest) + count - pos - 1) = *(static_cast<const uint8_t*>(src) + count - pos - 1);
}
}
return dest;
}
#endif
void* memset(void* dest, int value, size_t count) noexcept
{

21
targets/_any/src/os/draw.cpp
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@ -16,11 +16,16 @@ void scrollVertical(int scrollY, const Pixel& fillColor) noexcept
if (scrollY == 0) {
return;
}
const std::ptrdiff_t pixelOffset = scrollY * gFramebuffer.getPitch();
if (scrollY > 0)
{
// std::memmove(gFramebuffer.getBase(), gFramebuffer.getBase() + pixelOffset, gFramebuffer.getBufferSize() - (4 * pixelOffset));
// std::memset(gFramebuffer.getBase() + pixelOffset, 0, )
const size_t bytesPerRow = gDoubleBuffer.getPitch() * sizeof(Pixel);
const size_t bytesToMove = (gDoubleBuffer.getHeight() - scrollY) * bytesPerRow;
const size_t byteDist = scrollY * bytesPerRow;
uint8_t* basePtr = reinterpret_cast<uint8_t*>(gDoubleBuffer.getBase());
std::memmove(basePtr, basePtr + byteDist, bytesToMove);
std::memset(basePtr + byteDist, 0, byteDist);
std::memcpy(gFramebuffer.getBase(), gDoubleBuffer.getBase(), gDoubleBuffer.getHeight() * bytesPerRow);
}
}
}
@ -108,11 +113,11 @@ void character(unsigned posX, unsigned posY, const psf::Font& font, char chr, co
void scrollBy(int scrollX, int scrollY, const Pixel& fillColor) noexcept
{
// if (scrollX == 0)
// {
// scrollVertical(scrollY, fillColor);
// return;
// }
if (scrollX == 0)
{
scrollVertical(scrollY, fillColor);
return;
}
const int width = static_cast<int>(gFramebuffer.getHeight());
const int height = static_cast<int>(gFramebuffer.getHeight());
const bool reverseX = scrollX < 0;

63
targets/x86_64/src/cstdlib/memory.s
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@ -3,25 +3,64 @@
.global memcpy
.type memcpy @function
// int memcpy(void* dest [%rdi], void* src [%rsi], size_t count [%rdx])
// void* memcpy(void* dest [%rdi], void* src [%rsi], size_t count [%rdx])
//
memcpy:
cmpq %rdx, 4
jl memcpy_bytes
movq (%rsi), %rax
movq %rax, (%rdi)
addq $4, %rsi
addq $4, %rdi
subq $4, %rdx
jmp memcpy
movq %rdi, %rax // return value
memcpy_qwords:
cmpq $8, %rdx // check if the remaining bytes are at least 8
jl memcpy_bytes // if not copy the remaining bytes per byte
movq (%rsi), %rcx // if yes, copy using movq
movq %rcx, (%rdi)
addq $8, %rsi
addq $8, %rdi
subq $8, %rdx
jmp memcpy_qwords
memcpy_bytes:
cmpq %rdx, 0
cmpq $0, %rdx
je memcpy_end
movb (%rsi), %ah
movb %ah, (%rdi)
movb (%rsi), %ch
movb %ch, (%rdi)
addq $1, %rsi
addq $1, %rdi
subq $1, %rdx
jmp memcpy_bytes
memcpy_end:
ret
.global memmove
.type memmove @function
// void* memmove(void* dest [%rdi], void* src [%rsi], size_t count [%rdx])
//
memmove:
movq %rdi, %rax // preserve dest as return value
cmpq %rsi, %rdi // check if dest > src
jg memmove_backward // if yes, do everything backwards
movq %rsi, %rcx // check if (src - dest) < 8
subq %rdi, %rcx
cmpq $8, %rdi
jl memcpy_bytes // if yes, we have to do a bytewise copy
jmp memcpy_qwords // otherwise copy whole qwords
memmove_backward: // dest > src, copy backwards
addq %rdx, %rdi // dest = dest + count
addq %rdx, %rsi // src = src + count
memmove_qwords:
cmpq $8, %rdx // check if the remaining bytes are at least 8
jl memmove_bytes // if not copy the remaining bytes per byte
movq -8(%rsi), %rcx // if yes, copy using movq
movq %rcx, -8(%rdi)
subq $8, %rsi
subq $8, %rdi
subq $8, %rdx
jmp memmove_qwords
memmove_bytes:
cmpq $0, %rdx
je memmove_end
movb (%rsi), %ch
movb %ch, (%rdi)
subq $1, %rsi
subq $1, %rdi
subq $1, %rdx
jmp memmove_bytes
memmove_end:
ret