asm { PUT_DEC_U64:: //RAX is number to print in decimal. //Preserves all regs. PUSH RBP MOV RBP,RSP SUB RSP,24 //24 char buffer on stack //Save regs which C code is free to clobber. We don't have to for C callers, //but this function will be nice for ASM callers if it saves all regs. PUSH_C_REGS PUSH RSI //See REGG_LOCAL_VARS&REGG_LOCAL_NON_PTR_VARS LEA RSI,-1[RBP] //Load addr of end of buffer. //We picked RSI because of PUT_STR //We'll move bwd MOV U8 [RSI],0 //Terminator TEST RAX,RAX //Special case -- zero JNZ @@05 DEC RSI MOV U8 [RSI],'0' JMP @@15 @@05: MOV RBX,10 //Divides by 10 @@10: XOR RDX,RDX DIV RBX //RAX=(RDX:RAX)/RBX with remainder in RDX ADD RDX,'0' DEC RSI MOV U8 [RSI],DL TEST RAX,RAX JNZ @@10 @@15: CALL PUT_STR POP RSI POP_C_REGS LEAVE RET _DO_IT:: //The convention is C-callable routines have underscores. MOV RAX,122333221 CALL PUT_DEC_U64 MOV RAX,'\n' CALL PUT_CHARS RET } Call(_DO_IT);