.text

! Master Vector Base Table at 0x06000000

        .long   mstart      /* Cold Start PC */
        .long   0x06040000  /* Cold Start SP */
        .long   mstart      /* Manual Reset PC */
        .long   0x06040000  /* Manual Reset SP */
        .long   master_e4   /* Illegal instruction */
        .long   master_e5   /* reserved */
        .long   master_e6   /* Invalid slot instruction */
        .long   master_e7   /* reserved */
        .long   master_e8   /* reserved */
        .long   master_e9   /* CPU address error */
        .long   master_e10  /* DMA address error */
        .long   master_e11  /* NMI vector */
        .long   master_e12  /* User break vector */
.rept 19
        .long   main_err    /* reserved */
.endr
.rept 32
        .long   main_err    /* TRAPA #32-63 */
.endr
        .long   main_irq    /* Level 1 IRQ */
        .long   main_irq    /* Level 2 & 3 IRQ's */
        .long   main_irq    /* Level 4 & 5 IRQ's */
        .long   main_irq    /* PWM interupt */
        .long   main_irq    /* Command interupt */
        .long   main_irq    /* H Blank interupt */
        .long   main_irq    /* V Blank interupt */
        .long   main_irq    /* Reset Button */
.rept 56
        .long   main_err    /* peripherals */
.endr

! Slave Vector Base Table at 0x06000200

        .long   sstart      /* Cold Start PC */
        .long   0x0603f800  /* Cold Start SP */
        .long   sstart      /* Manual Reset PC */
        .long   0x0603f800  /* Manual Reset SP */
        .long   slave_e4    /* Illegal instruction */
        .long   slave_e5    /* reserved */
        .long   slave_e6    /* Invalid slot instruction */
        .long   slave_e7    /* reserved */
        .long   slave_e8    /* reserved */
        .long   slave_e9    /* CPU address error */
        .long   slave_e10   /* DMA address error */
        .long   slave_e11   /* NMI vector */
        .long   slave_e12   /* User break vector */
.rept 19
        .long   slave_err   /* reserved */
.endr
.rept 32
        .long   slave_err   /* TRAPA #32-63 */
.endr
        .long   slave_irq   /* Level 1 IRQ */
        .long   slave_irq   /* Level 2 & 3 IRQ's */
        .long   slave_irq   /* Level 4 & 5 IRQ's */
        .long   slave_irq   /* PWM interupt */
        .long   slave_irq   /* Command interupt */
        .long   slave_irq   /* H Blank interupt */
        .long   slave_irq   /* V Blank interupt */
        .long   slave_irq   /* Reset Button */
.rept 56
        .long   slave_err   /* peripherals */
.endr

! trashes r0
.macro mov_bc const ofs reg
        mov     #\const, r0
.if \ofs == 0
        mov.b   r0, @\reg
.else
        mov.b   r0, @(\ofs, \reg)
.endif
.endm

! Stacks set up by BIOS

! The main SH2 starts here at 0x06000400

mstart:
        bra     xstart
        mov     #0, r4

! The slave SH2 starts here at 0x06000404

sstart:
        mov     #1, r4

xstart:
.if 0
! cache init - done by BIOS with single 0x11 write
        mov.l   l_cctl, r1   /* cache */
        mov_bc  0x00, 0, r1  /* disable */
        mov.b   @r1, r0      /* dummy read */
        mov_bc  0x10, 0, r1  /* purge */
        mov.b   @r1, r0
        mov_bc  0x01, 0, r1  /* enable */
.endif
        mov     #0xd0, r0    /* enable irqs */
        ldc     r0, sr
        mov.l   l_main_c, r0
        jmp     @r0
        nop

main_irq:
        mov.l   r0, @-r15

        stc     sr, r0       /* SR holds IRQ level in I3-I0 */
        shlr2   r0
        and     #0x38,r0
        cmp/eq  #0x38,r0
        bt      main_irq_vres
! todo
0:
        bra     0b
        nop

main_irq_vres:
        mov.w   r0, @(0x14, gbr)  /* ack */
        mov.b   @(7, gbr), r0     /* RV */
        tst     #1, r0
        bt      main_irq_ret

! Try to set FTOB pin that's wired to 32X hard reset.
! Doesn't seem to be working right though, it somehow disturbs
! 68k reset PC fetch which mysteriously ends up at range
! 2c8 - 304 in multiples of 4, proportionally to reset delay
! (0 - ~300 (?) sh2 cycles). Longer delay just hangs, presumably
! at 880200?
        mov.l   l_frt, r1
        mov_bc  0xf1, 7, r1  /* TOCR sel OCRB, pin on B match */
        mov     #0, r0
        mov.b   r0, @(4, r1) /* OCRB H - output compare B */
        mov.b   r0, @(5, r1) /* OCRB L */
        mov.b   r0, @(2, r1) /* FRC H */
        mov.b   r0, @(3, r1) /* FRC L */
        mov.b   @(7, r1), r0
! sleep - docs say not to use
!        sleep
0:
        bra     0b
        nop

main_irq_ret:
        rte
        mov.l   @r15+, r0

.global _read_frt
_read_frt:
        mov.l   l_frt, r2
        mov.b   @(2, r2), r0
        extu.b  r0, r1
        mov.b   @(3, r2), r0
        extu.b  r0, r0
        shll8   r1
        rts
        or      r1, r0

.align 2
l_cctl:
        .long   0xFFFFFE92
l_frt:
        .long   0xFFFFFE10
l_main_c:
        .long   _main_c

! dummy
.global _start
_start:

main_err:
        bra     do_exc_master
        mov     #0xff, r0
slave_err:
slave_irq:
        bra     do_exc_slave
        mov     #0xff, r0

.macro exc_master num
master_e\num:
        bra     do_exc_master
        mov     #\num, r0
.endm

.macro exc_slave num
slave_e\num:
        bra     do_exc_slave
        mov     #\num, r0
.endm

exc_master 4
exc_master 5
exc_master 6
exc_master 7
exc_master 8
exc_master 9
exc_master 10
exc_master 11
exc_master 12

exc_slave 4
exc_slave 5
exc_slave 6
exc_slave 7
exc_slave 8
exc_slave 9
exc_slave 10
exc_slave 11
exc_slave 12

do_exc_master:
        mov.w   r0, @(0x2c, gbr)
0:
        bra     0b
        nop

do_exc_slave:
        mov.w   r0, @(0x2e, gbr)
0:
        bra     0b
        nop

.global _spin
_spin:
        dt      r4
        bf      _spin
        rts
        nop

! vim:ts=8:sw=8:expandtab