TempleOSCDV4.11.ISO

Demo/Asm/PutDec.HC

@@ -0,0 +1,49 @@
+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
+
+//$LK,"Save regs",A="FF:::/Kernel/KernelA.HH,PUSH_C_REGS"$ 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 $LK,"REGG_LOCAL_VARS",A="MN:REGG_LOCAL_VARS"$&$LK,"REGG_LOCAL_NON_PTR_VARS",A="MN:REGG_LOCAL_NON_PTR_VARS"$
+	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);