44 lines
893 B
C++
44 lines
893 B
C++
asm {
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PUT_DEC_U64::
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//RAX is number to print in decimal.
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//Preserves all regs.
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ENTER 24 //24 char buffer on stack
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PUSH_C_REGS //$LK,"Save regs","FF:::/SparrowOS/OSMain/Adam1a.HPP.Z,PUSH_C_REGS"$ which C code is free to clobber
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PUSH RSI //This reg is not saved.
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LEA RSI,-1[RBP] //Load addr of end of buffer.
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//We picked RSI because of PUT_STR
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//We'll move backward
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MOV U8 [RSI],0 //Terminator
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OR RAX,RAX //Special case -- zero
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JNZ @@05
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DEC RSI
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MOV U8 [RSI],'0'
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JMP @@15
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@@05: MOV RBX,10 //Divides by 10
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@@10: XOR RDX,RDX
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DIV RBX //RAX=(RDX:RAX)/RBX with remainder in RDX
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ADD RDX,'0'
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DEC RSI
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MOV U8 [RSI],DL
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OR RAX,RAX
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JNZ @@10
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@@15: CALL &PUT_STR
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POP RSI
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POP_C_REGS
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LEAVE
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RET
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_DO_IT:: //The convention is C-callable routines have underscores.
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MOV RAX,122333221
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CALL PUT_DEC_U64
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PUSH 1
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CALL &NewLine //Print one carriage return
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RET
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}
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Call(_DO_IT);
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