Mercurial > hg > index.cgi
changeset 12:981a5ed51a4d
Enable interrupts during startup and add handler to process keyboard
| author | William Astle <lost@l-w.ca> |
|---|---|
| date | Sun, 06 Nov 2022 12:05:33 -0700 |
| parents | b2212c9de7b7 |
| children | 6b3609304712 |
| files | src/lwbasic.s |
| diffstat | 1 files changed, 23 insertions(+), 2 deletions(-) [+] |
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--- a/src/lwbasic.s Sun Nov 06 00:27:04 2022 -0600 +++ b/src/lwbasic.s Sun Nov 06 12:05:33 2022 -0700 @@ -403,9 +403,13 @@ stx RSTVEC lda #0x55 ; activate warm start handler sta RSTFLG + ldx #irqhandler ; enable IRQ handler with a JMP at the vector + lda #0x7e + sta IRQVEC ; set JMP instruction + stx IRQVEC+1 ; set address ldx #greeting ; display greeting jsr console_outstr - bra * + bra warmstartb ; finish up initialization ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; Warm start handling ifdef COCO3 @@ -414,7 +418,10 @@ warmstart nop ; flag warm start routine as valid endc jsr console_clear ; clear screen - jsr keyb_reset ; reset the keyboard +warmstartb jsr keyb_reset ; reset the keyboard + lda #0x35 ; enable VSYNC interrupt in PIA + sta PIA0.CB + andcc #0xaf ; enable interrupts at the cpu bra * ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; System startup message @@ -424,6 +431,20 @@ fcc 'WIZARD ENTERPRISES INC.\r\n' fcn '\n' ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +; IRQ handler +; +; Note that the interrupt flag in the PIA is cleared at the start of the interrupt handler. That means that if it takes +; a long time to process this interrupt, or processing this interrupt was delayed somewhat, it is far less likely that +; an interrupt gets missed. In that case, we may end up re-interrupting immediately on RTI, but it should reduce the +; number of missed interrupts. +irqhandler lda PIA0.CB ; was it VSYNC? + bmi irqhandler0 ; brif so + lda PIA0.DA ; clear HSYNC flag so we don't get stuck if it gets enabled + rti +irqhandler0 lda PIA0.DB ; clear VSYNC flag + bsr keyb_read ; go handle the keyboard + rti +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; Console keyboard input driver ; ; Reset the keyboard state, which means clearing the buffer and state flags