구차니의 잡동사니 모음

문득 생각나서 Branch prediction을 8051에서 지원하나 찾아보다가 발견

다르게 보면.. ARM 계열의 성능이 좋긴 좋은거였구나..(Cortex-M3,M4)라는 생각이 든다.

[링크 : https://www.design-reuse.com/news/33780/8051-microcontroller-ip-core.html]

[링크 : http://www.cast-inc.com/ip-cores/8051s/s8051xc3/index.html]

클래식이던 확장이던 IDATA와 DATA는 존재하는데

DATA와  IDATA의 차이에 대해서 keil 사이트에 설명이 모호한데

direct와 indirect의 차이로 설명이 된다. 근데.. 감이 안오는데....

IDATA

This memory is indirectly accessed using 8-bit addresses and is the on-chip RAM of the 8051.

DATA

This memory is directly accessed using 8-bit addresses and is the on-chip RAM of the 8051.

[링크 : http://www.keil.com/support/man/docs/c51/c51_le_memtypes.htm]

    [링크 : http://www.keil.com/support/man/docs/c51/c51_le_data.htm] DATA

    [링크 : http://www.keil.com/support/man/docs/c51/c51_le_idata.htm] IDATA

어라..? IDATA accessed with @R0 or @R1

레지스터에 값을 저장하고 그 값을 통해 간접 접근을 하는 거군?

[링크 : http://measure.feld.cvut.cz/.../A51___Keil_Macro_Assembler_and_Utilities.pdf]

for(idx = 0; idx < len; idx++)
{
	tempUnicode = input[idx];
	if(0x0020 <= tempUnicode && tempUnicode < 0x0080)	res = (char)(tempUnicode & 0x00FF);
	else if(tempUnicode == 0x00E1)						res = 0x80;
	else if(tempUnicode == 0x00E0)						res = 0x81;
	...
	else if(0x0400 < tempUnicode && tempUnicode <= 0x045F)
	{
		switch(tempUnicode)
		{
			case 0x0401:	res = 192 +	0;	break;
			case 0x0402:	res = 192 +	1;	break;
			...
		}
	}
	else												res = ' ';
}

for(idx = 0; idx < len; idx++)
{
	tempUnicode = input[idx];
	if(0x0020 <= tempUnicode && tempUnicode < 0x0080)	res = (char)(tempUnicode & 0x00FF);
	else if(0x0400 < tempUnicode && tempUnicode <= 0x045F)
	{
		switch(tempUnicode)
		{
			case 0x0401:	res = 192 +	0;	break;
			case 0x0402:	res = 192 +	1;	break;
			...
		}
	}
	else if(tempUnicode == 0x00E1)						res = 0x80;
	else if(tempUnicode == 0x00E0)						res = 0x81;
	...
	else												res = ' ';
}

if(tempUnicode == 0x00E0)        output[out_idx] = 0x80;
else if(tempUnicode == 0x00E0) output[out_idx] = 0x80;
else if(tempUnicode == 0x00E0) output[out_idx] = 0x80;
...
else if(tempUnicode == 0x00E0) output[out_idx] = 0x80;
// 대략 128개

if(tempUnicode == 0x00E0)        res = 0x80;
else if(tempUnicode == 0x00E0) res = 0x80;
else if(tempUnicode == 0x00E0) res = 0x80;
...
else if(tempUnicode == 0x00E0) res = 0x80;
// 대략 128개

C51 Evaluation Tools

• You may not use the Evaluation Version of the µVision IDE/Debugger to create commercial products.
• The 8051 compiler, assembler, linker, and debugger are limited to 2 Kbytes of object code. Source code may be of any size.
• Programs that generate more than 2 Kbytes of object code will not compile, assemble, or link.
• The debugger supports programs that are 2 Kbytes or smaller.
• The startup code generated includes LJMPs. Code generated cannot be used in single-chip devices that support 2 Kbytes or less of program space.
• Programs start at offset 0x0800. Programs generated with the evaluation software may not be programmed into single-chip devices with less than 2 Kbytes of on-chip ROM.
• No hardware support for multiple DPTR registers is provided.
• No support for floating-point arithmetic and no support for user libraries is provided.
• No support for in-line assembly using #pragma ASM.
• The following components which are present in the PK51 Full Version are not included in the Evaluation Version: Linker for Code Banking, Library Manager, and RTX51 Tiny Real-time Operating System.