e5ae0c0e20
- Remove old/unused code. - Remove format string constructors. - Better win64 support (vsscanf, prefetch, etc). - Fix radix sort to sort -0 correctly. - Add misc utilities (constraints, timer, cpuinfo, introsort).
125 lines
3.2 KiB
Plaintext
125 lines
3.2 KiB
Plaintext
; MASM x64 version of
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; vsscanf for Win32
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; originally written 5/2003 by <mgix@mgix.com>
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;
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; This was done because MSVC does not accept inline assembly code
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; for the x64 platform, so this file implements almost the whole
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; module in assembly using the amd64 ABI
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;
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; 06/17/2008 by edgarv [at] nvidia com
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; Definition of memcpy
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memcpy PROTO dest:Ptr, src:Ptr, numbytes:QWORD
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; Definition of sscanf
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sscanf PROTO buffer:Ptr Byte, format:Ptr Byte, args:VARARG
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; Start a code segment named "_TEXT" by default
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.CODE
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; Entry point of our function: at this point we can use
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; named parameters
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ALIGN 16
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PUBLIC vsscanf_proxy_win64
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; Because the x64 code uses the fast call convention, only
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; the arguments beyond the 4th one are available from the stack.
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; The first four parameters are in RCX, RDX, R8 and R9
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; Parameters:
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; const char* buffer
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; const char* format
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; va_list argPtr
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; size_t count
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vsscanf_proxy_win64 PROC, \
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buffer:PTR Byte, format:PTR Byte, argPtr:PTR, count:QWORD
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; Allocates space for our local variable, savedRDP
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sub rsp, 08h
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; Copies the parameters from the registers to the memory: before warping to
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; sscanf we will call memcpy, and those registers can just dissapear!
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mov buffer, rcx
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mov format, rdx
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mov argPtr, r8
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mov count, r9
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; Allocate extra space in the stack for (2+count)*sizeof(void*),
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; this is (2+count)*(8)
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mov r10, r9
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add r10, 2 ; count += 2
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sal r10, 3 ; count *= 8
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add r10, 0fh ; To force alignment to 16bytes
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and r10, 0fffffffffffffff0h
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sub rsp, r10 ; Actual stack allocation
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; Continues by copying all the arguments in the "alloca" space
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mov [rsp], rcx ; newStack[0] = (void*)buffer;
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mov [rsp + 08h], rdx ; newStack[1] = (void*)format;
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; Calls memcpy(newStack+2, argPtr, count*sizeof(void*));
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mov rcx, rsp
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add rcx, 010h ; newStack+2
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mov rdx, r8 ; argPtr
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mov r8, r9
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sal r8, 3 ; count*sizeof(void*)
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; Prepares extra stack space as required by the ABI for 4 arguments, and calls memcpy
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sub rsp, 020h
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call memcpy
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; Restore the stack
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add rsp, 020h
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; Saves rsp in memory
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mov qword ptr [rbp - 8], rsp
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; Does exactly the same trick as before: warp into system sscanf with the new stack,
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; but this time we also setup the arguments in the registers according to the amd64 ABI
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; If there was at least one argument (after buffer and format), we need to copy that
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; to r8, and if there was a second one we must copy that to r9
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; (the first arguments to sscanf are always the buffer and the format)
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mov r10, count
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; Copy the first argument to r8 (if it exists)
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cmp r10, 0
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je args_memcpy
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mov r8, [rsp + 10h]
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; Copy the second argument to r9 (if it exists)
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cmp r10, 1
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je args_memcpy
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mov r9, [rsp + 18h]
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args_memcpy:
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; Copies the buffer and format to rcx and rdx
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mov rdx, [rsp + 08h]
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mov rcx, [rsp]
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; Finally, calls sscanf using the current stack
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call sscanf
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; At this point the return value is alreay in rax
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; Restores rsp
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mov rsp, qword ptr [rbp - 8]
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; Undoes the alloca
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add rsp, r10
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; Restores the space for local variables
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add rsp, 08h
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; Remember, the return value is already in rax since the sscanf call
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ret
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vsscanf_proxy_win64 ENDP
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END
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