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gerrit.devboardsforandroid.linaro.org / platform / external / u-boot / b783edaee8252bfdba3f7b3fd29519a81ce71e42 / . / board / w7o / post1.S
blob: d510cca1f6c85d7c9d69874e1670df2418d451ac [file] [log] [blame]
/*
* (C) Copyright 2001
* Bill Hunter, Wave 7 Optics, william.hunter@mediaone.net
* and
* Erik Theisen, Wave 7 Optics, etheisen@mindspring.com
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
/*
* Description:
* Routine to exercise memory for the bringing up of our boards.
*/
#include <config.h>
#include <ppc4xx.h>
#define _LINUX_CONFIG_H 1 /* avoid reading Linux autoconf.h file */
#include <ppc_asm.tmpl>
#include <ppc_defs.h>
#include <asm/cache.h>
#include <asm/mmu.h>
#include <watchdog.h>
#include "errors.h"
#define _ASMLANGUAGE
.globl test_sdram
.globl test_led
.globl log_stat
.globl log_warn
.globl log_err
.globl temp_uart_init
.globl post_puts
.globl disp_hex
/*****************************************************
******* Text Strings for low level printing ******
******* In section got2 *******
*****************************************************/
/*
* Define the text strings for errors and warnings.
* Switch to .data section.
*/
.section ".data"
err_str: .asciz "*** POST ERROR = "
warn_str: .asciz "*** POST WARNING = "
end_str: .asciz "\r\n"
/*
* Enter the labels in Global Entry Table (GOT).
* Switch to .got2 section.
*/
START_GOT
GOT_ENTRY(err_str)
GOT_ENTRY(warn_str)
GOT_ENTRY(end_str)
END_GOT
/*
* Switch back to .text section.
*/
.text
/****************************************
****************************************
******** LED register test ********
****************************************
***************************************/
test_led:
/* save the return info on stack */
mflr r0 /* Get link register */
stwu r1, -12(r1) /* Save back chain and move SP */
stw r0, +16(r1) /* Save link register */
stw r4, +8(r1) /* save R4 */
WATCHDOG_RESET /* Reset the watchdog */
addi r3, 0, ERR_FF /* first test value is ffff */
addi r4, r3, 0 /* save copy of pattern */
bl set_led /* store first test value */
bl get_led /* read it back */
xor. r4, r4, r3 /* compare to original */
#if defined(CONFIG_W7OLMC)
andi. r4, r4, 0x00ff /* lmc has 8 bits */
#else
andi. r4, r4, 0xffff /* lmg has 16 bits */
#endif
beq LED2 /* next test */
addi r3, 0, ERR_LED /* error code = 1 */
bl log_err /* display error and halt */
LED2: addi r3, 0, ERR_00 /* 2nd test value is 0000 */
addi r4, r3, 0 /* save copy of pattern */
bl set_led /* store first test value */
bl get_led /* read it back */
xor. r4, r4, r3 /* compare to original */
#if defined(CONFIG_W7OLMC)
andi. r4, r4, 0x00ff /* lmc has 8 bits */
#else
andi. r4, r4, 0xffff /* lmg has 16 bits */
#endif
beq LED3 /* next test */
addi r3, 0, ERR_LED /* error code = 1 */
bl log_err /* display error and halt */
LED3: /* restore stack and return */
lwz r0, +16(r1) /* Get saved link register */
mtlr r0 /* Restore link register */
lwz r4, +8(r1) /* restore r4 */
addi r1, r1, +12 /* Remove frame from stack */
blr /* Return to calling function */
/****************************************
****************************************
******** SDRAM TESTS ********
****************************************
***************************************/
test_sdram:
/* called with mem size in r3 */
/* save the return info on stack */
mflr r0 /* Get link register */
stwu r1, -16(r1) /* Save back chain and move SP */
stw r0, +20(r1) /* Save link register */
stmw r30, +8(r1) /* save R30,R31 */
/* r30 is log2(mem size) */
/* r31 is mem size */
/* take log2 of total mem size */
addi r31, r3, 0 /* save total mem size */
addi r30, 0, 0 /* clear r30 */
l2_loop:
srwi. r31, r31, 1 /* shift right 1 */
addi r30, r30, 1 /* count shifts */
bne l2_loop /* loop till done */
addi r30, r30, -1 /* correct for over count */
addi r31, r3, 0 /* save original size */
/* now kick the dog and test the mem */
WATCHDOG_RESET /* Reset the watchdog */
bl Data_Buster /* test crossed/shorted data lines */
addi r3, r30, 0 /* get log2(memsize) */
addi r4, r31, 0 /* get memsize */
bl Ghost_Buster /* test crossed/shorted addr lines */
addi r3, r31, 0 /* get mem size */
bl Bit_Buster /* check for bad internal bits */
/* restore stack and return */
lmw r30, +8(r1) /* Restore r30, r31 */
lwz r0, +20(r1) /* Get saved link register */
mtlr r0 /* Restore link register */
addi r1, r1, +16 /* Remove frame from stack */
blr /* Return to calling function */
/****************************************
******** sdram data bus test ********
***************************************/
Data_Buster:
/* save the return info on stack */
mflr r0 /* Get link register */
stwu r1, -24(r1) /* Save back chain and move SP */
stw r0, +28(r1) /* Save link register */
stmw r28, 8(r1) /* save r28 - r31 on stack */
/* r31 i/o register */
/* r30 sdram base address */
/* r29 5555 syndrom */
/* r28 aaaa syndrom */
/* set up led register for this test */
addi r3, 0, ERR_RAMG /* set led code to 1 */
bl log_stat /* store test value */
/* now test the dram data bus */
xor r30, r30, r30 /* load r30 with base addr of sdram */
addis r31, 0, 0x5555 /* load r31 with test value */
ori r31, r31, 0x5555
stw r31,0(r30) /* sto the value */
lwz r29,0(r30) /* read it back */
xor r29,r31,r29 /* compare it to original */
addis r31, 0, 0xaaaa /* load r31 with test value */
ori r31, r31, 0xaaaa
stw r31,0(r30) /* sto the value */
lwz r28,0(r30) /* read it back */
xor r28,r31,r28 /* compare it to original */
or r3,r28,r29 /* or together both error terms */
/*
* Now that we have the error bits,
* we have to decide which part they are in.
*/
bl get_idx /* r5 is now index to error */
addi r3, r3, ERR_RAMG
cmpwi r3, ERR_RAMG /* check for errors */
beq db_done /* skip if no errors */
bl log_err /* log the error */
db_done:
lmw r28, 8(r1) /* restore r28 - r31 from stack */
lwz r0, +28(r1) /* Get saved link register */
addi r1, r1, +24 /* Remove frame from stack */
mtlr r0 /* Restore link register */
blr /* Return to calling function */
/****************************************************
******** test for address ghosting in dram ********
***************************************************/
Ghost_Buster:
/* save the return info on stack */
mflr r0 /* Get link register */
stwu r1, -36(r1) /* Save back chain and move SP */
stw r0, +40(r1) /* Save link register */
stmw r25, 8(r1) /* save r25 - r31 on stack */
/* r31 = scratch register */
/* r30 is main referance loop counter,
0 to 23 */
/* r29 is ghost loop count, 0 to 22 */
/* r28 is referance address */
/* r27 is ghost address */
/* r26 is log2 (mem size) =
number of byte addr bits */
/* r25 is mem size */
/* save the log2(mem size) and mem size */
addi r26, r3, 0 /* r26 is number of byte addr bits */
addi r25, r4, 0 /* r25 is mem size in bytes */
/* set the leds for address ghost test */
addi r3, 0, ERR_ADDG
bl set_led
/* first fill memory with zeros */
srwi r31, r25, 2 /* convert bytes to longs */
mtctr r31 /* setup byte counter */
addi r28, 0, 0 /* start at address at 0 */
addi r31, 0, 0 /* data value = 0 */
clr_loop:
stw r31, 0(r28) /* Store zero value */
addi r28, r28, 4 /* Increment to next word */
andi. r27, r28, 0xffff /* check for 2^16 loops */
bne clr_skip /* if not there, then skip */
WATCHDOG_RESET /* kick the dog every now and then */
clr_skip:
bdnz clr_loop /* Round and round... */
/* now do main test */
addi r30, 0, 0 /* start referance counter at 0 */
outside:
/*
* Calculate the referance address
* the referance address is calculated by setting the (r30-1)
* bit of the base address
* when r30=0, the referance address is the base address.
* thus the sequence 0,1,2,4,8,..,2^(n-1)
* setting the bit is done with the following shift functions.
*/
WATCHDOG_RESET /* Reset the watchdog */
addi r31, 0, 1 /* r31 = 1 */
slw r28, r31, r30 /* set bit coresponding to loop cnt */
srwi r28, r28, 1 /* then shift it right one so */
/* we start at location 0 */
/* fill referance address with Fs */
addi r31, 0, 0x00ff /* r31 = one byte of set bits */
stb r31,0(r28) /* save ff in referance address */
/* ghost (inner) loop, now check all posible ghosted addresses */
addi r29, 0, 0 /* start ghosted loop counter at 0 */
inside:
/*
* Calculate the ghost address by flipping one
* bit of referance address. This gives the
* sequence 1,2,4,8,...,2^(n-1)
*/
addi r31, 0, 1 /* r31 = 1 */
slw r27, r31, r29 /* set bit coresponding to loop cnt */
xor r27, r28, r27 /* ghost address = ref addr with
bit flipped*/
/* now check for ghosting */
lbz r31,0(r27) /* get content of ghost addr */
cmpwi r31, 0 /* compare read value to 0 */
bne Casper /* we found a ghost! */
/* now close ghost ( inner ) loop */
addi r29, r29, 1 /* increment inner loop counter */
cmpw r29, r26 /* check for last inner loop */
blt inside /* do more inner loops */
/* now close referance ( outer ) loop */
addi r31, 0, 0 /* r31 = zero */
stb r31, 0(28) /* zero out the altered address loc. */
/*
* Increment and check for end, count is zero based.
* With the ble, this gives us one more loops than
* address bits for sequence 0,1,2,4,8,...2^(n-1)
*/
addi r30, r30, 1 /* increment outer loop counter */
cmpw r30, r26 /* check for last inner loop */
ble outside /* do more outer loops */
/* were done, lets go home */
b gb_done
Casper: /* we found a ghost !! */
addi r3, 0, ERR_ADDF /* get indexed error message */
bl log_err /* log error led error code */
gb_done: /* pack your bags, and go home */
lmw r25, 8(r1) /* restore r25 - r31 from stack */
lwz r0, +40(r1) /* Get saved link register */
addi r1, r1, +36 /* Remove frame from stack */
mtlr r0 /* Restore link register */
blr /* Return to calling function */
/****************************************************
******** SDRAM data fill tests **********
***************************************************/
Bit_Buster:
/* called with mem size in r3 */
/* save the return info on stack */
mflr r0 /* Get link register */
stwu r1, -16(r1) /* Save back chain and move SP */
stw r0, +20(r1) /* Save link register */
stw r4, +8(r1) /* save R4 */
stw r5, +12(r1) /* save r5 */
addis r5, r3, 0 /* save mem size */
/* Test 55555555 */
addi r3, 0, ERR_R55G /* set up error code in case we fail */
bl log_stat /* store test value */
addis r4, 0, 0x5555
ori r4, r4, 0x5555
bl fill_test
/* Test aaaaaaaa */
addi r3, 0, ERR_RAAG /* set up error code in case we fail */
bl log_stat /* store test value */
addis r4, 0, 0xAAAA
ori r4, r4, 0xAAAA
bl fill_test
/* Test 00000000 */
addi r3, 0, ERR_R00G /* set up error code in case we fail */
bl log_stat /* store test value */
addis r4, 0, 0
ori r4, r4, 0
bl fill_test
/* restore stack and return */
lwz r5, +12(r1) /* restore r4 */
lwz r4, +8(r1) /* restore r4 */
lwz r0, +20(r1) /* Get saved link register */
addi r1, r1, +16 /* Remove frame from stack */
mtlr r0 /* Restore link register */
blr /* Return to calling function */
/****************************************************
******** fill test ********
***************************************************/
/* tests memory by filling with value, and reading back */
/* r5 = Size of memory in bytes */
/* r4 = Value to write */
/* r3 = Error code */
fill_test:
mflr r0 /* Get link register */
stwu r1, -32(r1) /* Save back chain and move SP */
stw r0, +36(r1) /* Save link register */
stmw r27, 8(r1) /* save r27 - r31 on stack */
/* r31 - scratch register */
/* r30 - memory address */
mr r27, r3
mr r28, r4
mr r29, r5
WATCHDOG_RESET /* Reset the watchdog */
/* first fill memory with Value */
srawi r31, r29, 2 /* convert bytes to longs */
mtctr r31 /* setup counter */
addi r30, 0, 0 /* Make r30 = addr 0 */
ft_0: stw r28, 0(r30) /* Store value */
addi r30, r30, 4 /* Increment to next word */
andi. r31, r30, 0xffff /* check for 2^16 loops */
bne ft_0a /* if not there, then skip */
WATCHDOG_RESET /* kick the dog every now and then */
ft_0a: bdnz ft_0 /* Round and round... */
WATCHDOG_RESET /* Reset the watchdog */
/* Now confirm Value is in memory */
srawi r31, r29, 2 /* convert bytes to longs */
mtctr r31 /* setup counter */
addi r30, 0, 0 /* Make r30 = addr 0 */
ft_1: lwz r31, 0(r30) /* get value from memory */
xor. r31, r31, r28 /* Writen = Read ? */
bne ft_err /* If bad, than halt */
addi r30, r30, 4 /* Increment to next word */
andi. r31, r30, 0xffff /* check for 2^16 loops*/
bne ft_1a /* if not there, then skip */
WATCHDOG_RESET /* kick the dog every now and then */
ft_1a: bdnz ft_1 /* Round and round... */
WATCHDOG_RESET /* Reset the watchdog */
b fill_done /* restore and return */
ft_err: addi r29, r27, 0 /* save current led code */
addi r27, r31, 0 /* get pattern in r27 */
bl get_idx /* get index from r27 */
add r27, r27, r29 /* add index to old led code */
bl log_err /* output led err code, halt CPU */
fill_done:
lmw r27, 8(r1) /* restore r27 - r31 from stack */
lwz r0, +36(r1) /* Get saved link register */
addi r1, r1, +32 /* Remove frame from stack */
mtlr r0 /* Restore link register */
blr /* Return to calling function */
/****************************************************
******* get error index from r3 pattern ********
***************************************************/
get_idx: /* r3 = (MSW(r3) !=0)*2 +
(LSW(r3) !=0) */
/* save the return info on stack */
mflr r0 /* Get link register */
stwu r1, -12(r1) /* Save back chain and move SP */
stw r0, +16(r1) /* Save link register */
stw r4, +8(r1) /* save R4 */
andi. r4, r3, 0xffff /* check for lower bits */
beq gi2 /* skip if no bits set */
andis. r4, r3, 0xffff /* check for upper bits */
beq gi3 /* skip if no bits set */
addi r3, 0, 3 /* both upper and lower bits set */
b gi_done
gi2: andis. r4, r3, 0xffff /* check for upper bits*/
beq gi4 /* skip if no bits set */
addi r3, 0, 2 /* only upper bits set */
b gi_done
gi3: addi r3, 0, 1 /* only lower bits set */
b gi_done
gi4: addi r3, 0, 0 /* no bits set */
gi_done:
/* restore stack and return */
lwz r0, +16(r1) /* Get saved link register */
mtlr r0 /* Restore link register */
lwz r4, +8(r1) /* restore r4 */
addi r1, r1, +12 /* Remove frame from stack */
blr /* Return to calling function */
/****************************************************
******** set LED to R5 and hang ********
***************************************************/
log_stat: /* output a led code and continue */
set_led:
/* save the return info on stack */
mflr r0 /* Get link register */
stwu r1, -12(r1) /* Save back chain and move SP */
stw r0, +16(r1) /* Save link register */
stw r4, +8(r1) /* save R4 */
addis r4, 0, 0xfe00 /* LED buffer is at 0xfe000000 */
#if defined(CONFIG_W7OLMG) /* only on gateway, invert outputs */
xori r3,r3, 0xffff /* complement led code, active low */
sth r3, 0(r4) /* store first test value */
xori r3,r3, 0xffff /* complement led code, active low */
#else /* if not gateway, then don't invert */
sth r3, 0(r4) /* store first test value */
#endif
/* restore stack and return */
lwz r0, +16(r1) /* Get saved link register */
mtlr r0 /* Restore link register */
lwz r4, +8(r1) /* restore r4 */
addi r1, r1, +12 /* Remove frame from stack */
blr /* Return to calling function */
get_led:
/* save the return info on stack */
mflr r0 /* Get link register */
stwu r1, -12(r1) /* Save back chain and move SP */
stw r0, +16(r1) /* Save link register */
stw r4, +8(r1) /* save R4 */
addis r4, 0, 0xfe00 /* LED buffer is at 0xfe000000 */
lhz r3, 0(r4) /* store first test value */
#if defined(CONFIG_W7OLMG) /* only on gateway, invert inputs */
xori r3,r3, 0xffff /* complement led code, active low */
#endif
/* restore stack and return */
lwz r0, +16(r1) /* Get saved link register */
mtlr r0 /* Restore link register */
lwz r4, +8(r1) /* restore r4 */
addi r1, r1, +12 /* Remove frame from stack */
blr /* Return to calling function */
log_err: /* output the error and hang the board ( for now ) */
/* save the return info on stack */
mflr r0 /* Get link register */
stwu r1, -12(r1) /* Save back chain and move SP */
stw r0, +16(r1) /* Save link register */
stw r3, +8(r1) /* save a copy of error code */
bl set_led /* set the led pattern */
GET_GOT /* get GOT address in r14 */
lwz r3,GOT(err_str) /* get address of string */
bl post_puts /* output the warning string */
lwz r3, +8(r1) /* get error code */
addi r4, 0, 2 /* set disp length to 2 nibbles */
bl disp_hex /* output the error code */
lwz r3,GOT(end_str) /* get address of string */
bl post_puts /* output the warning string */
halt:
b halt /* hang */
/* restore stack and return */
lwz r0, +16(r1) /* Get saved link register */
mtlr r0 /* Restore link register */
addi r1, r1, +12 /* Remove frame from stack */
blr /* Return to calling function */
log_warn: /* output a warning, then continue with operations */
/* save the return info on stack */
mflr r0 /* Get link register */
stwu r1, -16(r1) /* Save back chain and move SP */
stw r0, +20(r1) /* Save link register */
stw r3, +8(r1) /* save a copy of error code */
stw r14, +12(r1) /* save a copy of r14 (used by GOT) */
bl set_led /* set the led pattern */
GET_GOT /* get GOT address in r14 */
lwz r3,GOT(warn_str) /* get address of string */
bl post_puts /* output the warning string */
lwz r3, +8(r1) /* get error code */
addi r4, 0, 2 /* set disp length to 2 nibbles */
bl disp_hex /* output the error code */
lwz r3,GOT(end_str) /* get address of string */
bl post_puts /* output the warning string */
addis r3, 0, 64 /* has a long delay */
mtctr r3
log_2:
WATCHDOG_RESET /* this keeps dog from barking, */
/* and takes time */
bdnz log_2 /* loop till time expires */
/* restore stack and return */
lwz r0, +20(r1) /* Get saved link register */
lwz r14, +12(r1) /* restore r14 */
mtlr r0 /* Restore link register */
addi r1, r1, +16 /* Remove frame from stack */
blr /* Return to calling function */
/*******************************************************************
* temp_uart_init
* Temporary UART initialization routine
* Sets up UART0 to run at 9600N81 off of the internal clock.
* R3-R4 are used.
******************************************************************/
temp_uart_init:
/* save the return info on stack */
mflr r0 /* Get link register */
stwu r1, -8(r1) /* Save back chain and move SP */
stw r0, +12(r1) /* Save link register */
addis r3, 0, 0xef60
ori r3, r3, 0x0303 /* r3 = UART0_LCR */
addi r4, 0, 0x83 /* n81 format, divisor regs enabled */
stb r4, 0(r3)
/* set baud rate to use internal clock,
baud = (200e6/16)/31/42 = 9600 */
addis r3, 0, 0xef60 /* Address of baud divisor reg */
ori r3, r3, 0x0300 /* UART0_DLM */
addi r4, 0, +42 /* uart baud divisor LSB = 93 */
stb r4, 0(r3) /* baud = (200 /16)/14/93 */
addi r3, r3, 0x0001 /* uart baud divisor addr */
addi r4, 0, 0
stb r4, 0(r3) /* Divisor Latch MSB = 0 */
addis r3, 0, 0xef60
ori r3, r3, 0x0303 /* r3 = UART0_LCR */
addi r4, 0, 0x03 /* n81 format, tx/rx regs enabled */
stb r4, 0(r3)
/* output a few line feeds */
addi r3, 0, '\n' /* load line feed */
bl post_putc /* output the char */
addi r3, 0, '\n' /* load line feed */
bl post_putc /* output the char */
/* restore stack and return */
lwz r0, +12(r1) /* Get saved link register */
mtlr r0 /* Restore link register */
addi r1, r1, +8 /* Remove frame from stack */
blr /* Return to calling function */
/**********************************************************************
** post_putc
** outputs charactor in R3
** r3 returns the error code ( -1 if there is an error )
*********************************************************************/
post_putc:
/* save the return info on stack */
mflr r0 /* Get link register */
stwu r1, -20(r1) /* Save back chain and move SP */
stw r0, +24(r1) /* Save link register */
stmw r29, 8(r1) /* save r29 - r31 on stack
r31 - uart base address
r30 - delay counter
r29 - scratch reg */
addis r31, 0, 0xef60 /* Point to uart base */
ori r31, r31, 0x0300
addis r30, 0, 152 /* Load about 10,000,000 ticks. */
pputc_lp:
lbz r29, 5(r31) /* Read Line Status Register */
andi. r29, r29, 0x20 /* Check THRE status */
bne thre_set /* Branch if FIFO empty */
addic. r30, r30, -1 /* Decrement and check if empty. */
bne pputc_lp /* Try, try again */
addi r3, 0, -1 /* Load error code for timeout */
b pputc_done /* Bail out with error code set */
thre_set:
stb r3, 0(r31) /* Store character to UART */
addi r3, 0, 0 /* clear error code */
pputc_done:
lmw r29, 8(r1) /*restore r29 - r31 from stack */
lwz r0, +24(r1) /* Get saved link register */
addi r1, r1, +20 /* Remove frame from stack */
mtlr r0 /* Restore link register */
blr /* Return to calling function */
/****************************************************************
post_puts
Accepts a null-terminated string pointed to by R3
Outputs to the serial port until 0x00 is found.
r3 returns the error code ( -1 if there is an error )
*****************************************************************/
post_puts:
/* save the return info on stack */
mflr r0 /* Get link register */
stwu r1, -12(r1) /* Save back chain and move SP */
stw r0, +16(r1) /* Save link register */
stw r31, 8(r1) /* save r31 - char pointer */
addi r31, r3, 0 /* move pointer to R31 */
pputs_nxt:
lbz r3, 0(r31) /* Get next character */
addic. r3, r3, 0 /* Check for zero */
beq pputs_term /* bail out if zero */
bl post_putc /* output the char */
addic. r3, r3, 0 /* check for error */
bne pputs_err
addi r31, r31, 1 /* point to next char */
b pputs_nxt /* loop till term */
pputs_err:
addi r3, 0, -1 /* set error code */
b pputs_end /* were outa here */
pputs_term:
addi r3, 0, 1 /* set success code */
/* restore stack and return */
pputs_end:
lwz r31, 8(r1) /* restore r27 - r31 from stack */
lwz r0, +16(r1) /* Get saved link register */
addi r1, r1, +12 /* Remove frame from stack */
mtlr r0 /* Restore link register */
blr /* Return to calling function */
/********************************************************************
***** disp_hex
***** Routine to display a hex value from a register.
***** R3 is value to display
***** R4 is number of nibbles to display ie 2 for byte 8 for (long)word
***** Returns -1 in R3 if there is an error ( ie serial port hangs )
***** Returns 0 in R3 if no error
*******************************************************************/
disp_hex:
/* save the return info on stack */
mflr r0 /* Get link register */
stwu r1, -16(r1) /* Save back chain and move SP */
stw r0, +20(r1) /* Save link register */
stmw r30, 8(r1) /* save r30 - r31 on stack */
/* r31 output char */
/* r30 uart base address */
addi r30, 0, 8 /* Go through 8 nibbles. */
addi r31, r3, 0
pputh_nxt:
rlwinm r31, r31, 4, 0, 31 /* Rotate next nibble into position */
andi. r3, r31, 0x0f /* Get nibble. */
addi r3, r3, 0x30 /* Add zero's ASCII code. */
cmpwi r3, 0x03a
blt pputh_out
addi r3, r3, 0x07 /* 0x27 for lower case. */
pputh_out:
cmpw r30, r4
bgt pputh_skip
bl post_putc
addic. r3, r3, 0 /* check for error */
bne pputh_err
pputh_skip:
addic. r30, r30, -1
bne pputh_nxt
xor r3, r3, r3 /* Clear error code */
b pputh_done
pputh_err:
addi r3, 0, -1 /* set error code */
pputh_done:
/* restore stack and return */
lmw r30, 8(r1) /* restore r30 - r31 from stack */
lwz r0, +20(r1) /* Get saved link register */
addi r1, r1, +16 /* Remove frame from stack */
mtlr r0 /* Restore link register */
blr /* Return to calling function */