gnupic: Bug in sumlation of BSF instruction in GPSIM?
Subject:
Bug in sumlation of BSF instruction in GPSIM?
From:
Wojtek Zabolotny ####@####.####
Date:
17 Sep 2000 10:28:35 -0000
Message-Id: <20000917122002.A601@wzab.nasz.dom>
Hi All,
I've just stated that GPSIM has problems with simulation of BSF instruction
on ports which are partially configured as inputs, and partially as outputs.
I've attached the simplest source which demonstrates the problem.
Port C bits [0..5] are outputs, [6,7] are inputs.
The BSF PORT C,5 instruction reads 0x1f (correctly) and writes back 0x20
(incorrectly). MPLAB simulates this example correctly.
Below is the output of GPSIM session:
gpsim - the GNUPIC simulator
version: 0.20.2
type help for help
gpsim>
gpsim> Loading /home/wzab/photohd/asm/demo1.cod
processing cod file /home/wzab/photohd/asm/demo1.cod
directory is "/home/wzab/photohd/asm"
filename is "demo1.cod"
f877 create
f874 create
setting cfg_word and cfg_modes ffff 1
setting cfg_word and cfg_modes 3f3a 0
--- Reset
16F877 0x0000 0x2840 goto 0x0040
cycle: 0x01
cycle: 0x02
16F877 0x0040 0x30FF movlw 0xff
wrote: 0xff to W
cycle: 0x03
16F877 0x0041 0x0087 movwf portc
read: 0xff from W
wrote: 0x00 to portc
cycle: 0x04
16F877 0x0042 0x1683 bsf status,5
read: 0x18 from status
wrote: 0x38 to status
cycle: 0x05
16F877 0x0043 0x30C0 movlw 0xc0
wrote: 0xc0 to W
cycle: 0x06
16F877 0x0044 0x0087 movwf trisc
read: 0xc0 from W
wrote: 0x3f to portc
wrote: 0xc0 to trisc
cycle: 0x07
16F877 0x0045 0x1283 bcf status,5
read: 0x38 from status
wrote: 0x18 to status
cycle: 0x08
16F877 0x0046 0x1687 bsf portc,5
read: 0x3f from portc
wrote: 0x20 to portc
cycle: 0x09
16F877 0x0047 0x2847 goto 0x0047
cycle: 0x0a
cycle: 0x0b
--
Greetings
Wojciech Zabolotny
http://www.ise.pw.edu.pl/~wzab
When buying hardware, ask the dealer if it is Open Source friendly!!!
http://www.openhardware.org
list p=16f877 ; list directive to define processor
include "p16f877.inc"
__CONFIG _CP_OFF & _WDT_OFF & _BODEN_OFF & _PWRTE_OFF & _HS_OSC & _WRT_ENABLE_ON & _LVP_OFF & _DEBUG_OFF & _CPD_OFF
ORG 0x000 ; processor reset vector
goto main
org 0x40
main movlw 0xff
movwf PORTC
bsf STATUS,RP0
movlw b'11000000'
movwf TRISC
bcf STATUS,RP0
bsf PORTC,5
loop goto loop
end
