Category : Assembly Language Source Code
Archive   : CAS8051.ZIP
Filename : INT.ASM

;;; kernel.lib
;;; /* Process stack. */
HW equ 6fh ;;; data 1 ;;; int **HW;
Stack equ 70h ;;; data 8 ;;; int *Stack[8];

;;; /* Interrupt descriptor table. */
SP_IE0 equ 79h ;;; data 1
SP_IE1 equ 7bh ;;; data 1
SP_EXF2 equ 7ch ;;; data 1
SP_CCF equ 7dh ;;; data 1
SP_BASE equ 7eh ;;; data $(data)

include "8051fa.h"

org 00h
ajmp Start

org 03h
mov R0, #SP_IE0
acall Resume
reti

org 13h
mov R0, #SP_IE1
acall Resume
reti

org 2bh
jnb EXF2, DidTF2
jnb TF2, DidEXF2
sjmp DidBoth

org 33h
jbc CCF0, DidCCF0
jbc CCF1, DidCCF1
jbc CCF2, DidCCF2
jbc CCF3, DidCCF3
jbc CCF4, DidCCF4
reti

DidBoth:
mov A, RCAP2H
jnb Acc.7, DidTF2 ;;; This determines if TF2 or EXF2 was first.
DidEXF2:
clr EXF2
mov R0, #SP_EXF2
acall Resume
reti
DidTF2:
clr TF2
reti

DidCCF0:
mov A, #'0'
acall Sto
mov A, #0
mov C, CEX0
sjmp CCX
DidCCF1:
mov A, #'1'
acall Sto
mov A, #1
mov C, CEX1
sjmp CCX
DidCCF2:
mov A, #'2'
acall Sto
mov A, #2
mov C, CEX2
sjmp CCX
DidCCF3:
mov A, #'3'
acall Sto
mov A, #3
mov C, CEX3
sjmp CCX
DidCCF4:
mov A, #'4'
acall Sto
mov A, #4
mov C, CEX4
CCX:
rlc A
mov R0, #SP_CCF
acall Resume
reti

Start: ;;; Install main(), set its return address to _Die().
mov HW, #Stack ;;; HW = &Stack[0];
mov SP, #(SP_BASE - 1) ;;; SP = SP_BASE - 1;
mov DPTR, #_Exit
push DPL
push DPH ;;; @SP++ = _Exit();
acall main
_Die:
orl PCon, #1
sjmp _Die

Pause: ;;; void Pause(int @@R0) {
mov @R0, SP ;;; @R0 = SP;
dec HW
mov R0, HW
mov SP, @R0 ;;; SP = @--HW;
ret ;;; "idle until resume";
Resume:
mov R1, HW
mov @R1, SP
inc HW ;;; @HW++ = SP;
mov SP, @R0 ;;; SP = @R0;
mov @R0, #(SP_BASE + 1) ;;; @R0 = SP_BASE + 1;
ret ;;; }

Spawn: ;;; int Spawn(int @R0, void *(DPTR())) {
mov R1, HW
mov @R1, SP
inc HW ;;; @HW++ = SP;
dec R0
mov SP, R0 ;;; SP = --R0;
acall _Enter ;;; (*DPTR)();
_Exit:
dec HW
mov R0, HW
mov SP, @R0 ;;; SP = @--HW;
ret ;;; }
_Enter:
push DPL
push DPH
ret

include "io.lib"

COUNTERS equ 13
COUNT_BASE equ 8
IE0s equ 8
IE1s equ 9
T2EXs equ 10
PCCF0s equ 11
NCCF0s equ 12
PCCF1s equ 13
NCCF1s equ 14
PCCF2s equ 15
NCCF2s equ 16
PCCF3s equ 17
NCCF3s equ 18
PCCF4s equ 19
NCCF4s equ 20
SetCounts:
acall scr_init
mov R0, #COUNT_BASE
mov R2, #COUNTERS
SetLoop:
mov A, #'0'
acall cputc
mov @R0, #0
inc R0
djnz R2, SetLoop
ret
IncCount:
mov Row, #0
mov Col, A
add A, #COUNT_BASE
mov R0, A
acall locate
inc @R0
cjne @R0, #10, XX
mov @R0, #0
XX:
mov A, @R0
add A, #'0'
acall cputc
ret

RowP equ 21
ColP equ 22
SetArr:
mov RowP, #1
mov ColP, #0
ret
Sto:
mov Row, RowP
mov Col, ColP
push ACC
acall locate
pop ACC
acall cputc
inc ColP
mov A, ColP
cjne A, #20, YY
mov ColP, #0
inc RowP
mov A, RowP
cjne A, #4, ZZ
mov RowP, #1
ZZ:
YY:
ret

;;; APPLICATION PROGRAM
TestIE0:
setb Int0 ;;; Latch Int0 for input.
clr PX0
setb IT0
setb EX0
LoopIE0:
mov A, #'f'
acall Sto
mov R0, #SP_IE0
acall Pause
mov A, #0
acall IncCount
mov A, #'g'
acall Sto
sjmp LoopIE0

TestIE1:
setb Int1 ;;; Latch Int1 for input.
clr PX1
setb IT1
setb EX1
LoopIE1:
mov A, #'h'
acall Sto
mov R0, #SP_IE1
acall Pause
mov A, #1
acall IncCount
mov A, #'i'
acall Sto
sjmp LoopIE1

TestT2EX:
setb T2EX ;;; Latch T2EX for input.
clr PT2
setb CP_RL2
clr C_T2
setb EXEN2
setb ET2
LoopT2EX:
mov A, #'j'
acall Sto
mov R0, #SP_EXF2
acall Pause
mov A, #2
acall IncCount
mov A, #'k'
acall Sto
sjmp LoopT2EX

TestCCF:
mov CCAPM0, #(CAPP + CAPN + ECCF)
mov CCAPM1, #(CAPP + CAPN + ECCF)
mov CCAPM2, #(CAPP + CAPN + ECCF)
mov CCAPM3, #(CAPP + CAPN + ECCF)
mov CCAPM4, #(CAPP + CAPN + ECCF) ;;; CCF raises on either edge.
setb CEX0
setb CEX1
setb CEX2
setb CEX3
setb CEX4
setb EC
clr PPC
LoopCCF:
mov A, #'l'
acall Sto
mov R0, #SP_CCF
acall Pause
add A, #3
acall IncCount
mov A, #'m'
acall Sto
sjmp LoopCCF

main:
acall SetCounts
acall SetArr
mov A, #'a'
acall Sto
mov R0, #90h
mov DPTR, #TestIE0
acall Spawn
mov A, #'b'
acall Sto
mov R0, #0a0h
mov DPTR, #TestIE1
acall Spawn
mov A, #'c'
acall Sto
mov R0, #0b0h
mov DPTR, #TestT2EX
acall Spawn
mov A, #'d'
acall Sto
mov R0, #0c0h
mov DPTR, #TestCCF
acall Spawn
mov A, #'e'
acall Sto
setb EA
ret
end