[picodrive.git] / pico / cd / memory_arm.s

@*
@* Memory I/O handlers for Sega/Mega CD emulation
@* (C) notaz, 2007-2009
@*
@* This work is licensed under the terms of MAME license.
@* See COPYING file in the top-level directory.
@*

.equiv PCM_STEP_SHIFT, 11

.text
.align 2

.global PicoReadM68k8_io
.global PicoReadM68k16_io
.global PicoWriteM68k8_io
.global PicoWriteM68k16_io

.global PicoReadS68k8_pr
.global PicoReadS68k16_pr
.global PicoWriteS68k8_pr
.global PicoWriteS68k16_pr

.global PicoReadM68k8_cell0
.global PicoReadM68k8_cell1
.global PicoReadM68k16_cell0
.global PicoReadM68k16_cell1
.global PicoWriteM68k8_cell0
.global PicoWriteM68k8_cell1
.global PicoWriteM68k16_cell0
.global PicoWriteM68k16_cell1

.global PicoReadS68k8_dec0
.global PicoReadS68k8_dec1
.global PicoReadS68k16_dec0
.global PicoReadS68k16_dec1
.global PicoWriteS68k8_dec_m0b0
.global PicoWriteS68k8_dec_m1b0
.global PicoWriteS68k8_dec_m2b0
.global PicoWriteS68k8_dec_m0b1
.global PicoWriteS68k8_dec_m1b1
.global PicoWriteS68k8_dec_m2b1
.global PicoWriteS68k16_dec_m0b0
.global PicoWriteS68k16_dec_m1b0
.global PicoWriteS68k16_dec_m2b0
.global PicoWriteS68k16_dec_m0b1
.global PicoWriteS68k16_dec_m1b1
.global PicoWriteS68k16_dec_m2b1

@ externs, just for reference
.extern Pico
.extern Read_CDC_Host
.extern m68k_reg_write8
.extern s68k_reg_read16
.extern s68k_reg_write8
.extern s68k_poll_adclk
.extern s68k_poll_detect
.extern gfx_cd_read
.extern gfx_cd_write16
.extern PicoCpuCS68k
.extern PicoRead8_io
.extern PicoRead16_io
.extern PicoWrite8_io
.extern PicoWrite16_io


@ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

@ utilities

@ r0=addr[in,out], r1,r2=tmp
.macro cell_map
    ands    r1, r0, #0x01c000
    ldrne   pc, [pc, r1, lsr #12]
    beq     0f                          @ most common?
    .long   0f
    .long   0f
    .long   0f
    .long   0f
    .long   1f
    .long   1f
    .long   2f
    .long   3f
1: @ x16 cells
    and     r1, r0, #0x7e00             @ col
    and     r2, r0, #0x01fc             @ row
    orr     r2, r2, #0x0400
    orr     r1, r2, r1, ror #13
    b       9f
2: @ x8 cells
    and     r1, r0, #0x3f00             @ col
    and     r2, r0, #0x00fc             @ row
    orr     r2, r2, #0x0600
    orr     r1, r2, r1, ror #12
    b       9f
3: @ x4 cells
    and     r1, r0, #0x1f80             @ col
    and     r2, r0, #0x007c             @ row
    orr     r1, r2, r1, ror #11
    and     r2, r0,#0x1e000
    orr     r1, r1, r2, lsr #6
    b       9f
0: @ x32 cells
    and     r1, r0, #0xfc00             @ col
    and     r2, r0, #0x03fc             @ row
    orr     r1, r2, r1, ror #14
9:
    and     r0, r0, #3
    orr     r0, r0, r1, ror #26         @ rol 4+2
.endm


@ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@


m_read_null:
    mov     r0, #0
    bx      lr


PicoReadM68k8_cell0:                    @ 0x220000 - 0x23ffff, cell arranged
    mov     r3, #0x0c0000
    b       0f

PicoReadM68k8_cell1:                    @ 0x220000 - 0x23ffff, cell arranged
    mov     r3, #0x0e0000
0:
    cell_map
    ldr     r1, =(Pico+0x22200)
    add     r0, r0, r3
    ldr     r1, [r1]
    eor     r0, r0, #1
    ldrb    r0, [r1, r0]
    bx      lr


PicoReadM68k8_io:
    and     r1, r0, #0xff00
    cmp     r1, #0x2000	              @ a120xx?
    bne     PicoRead8_io

    ldr     r1, =(Pico+0x22200)
    and     r0, r0, #0x3f
    ldr     r1, [r1]                  @ Pico.mcd (used everywhere)
    cmp     r0, #0x0e
    ldrlt   pc, [pc, r0, lsl #2]
    b       m_m68k_read8_hi
    .long   m_m68k_read8_r00
    .long   m_m68k_read8_r01
    .long   m_m68k_read8_r02
    .long   m_m68k_read8_r03
    .long   m_m68k_read8_r04
    .long   m_read_null               @ unused bits
    .long   m_m68k_read8_r06
    .long   m_m68k_read8_r07
    .long   m_m68k_read8_r08
    .long   m_m68k_read8_r09
    .long   m_read_null               @ reserved
    .long   m_read_null
    .long   m_m68k_read8_r0c
    .long   m_m68k_read8_r0d
m_m68k_read8_r00:
    add     r1, r1, #0x110000
    ldr     r0, [r1, #0x30]
    and     r0, r0, #0x04000000       @ we need irq2 mask state
    mov     r0, r0, lsr #19
    bx      lr
m_m68k_read8_r01:
    add     r1, r1, #0x110000
    add     r1, r1, #0x002200
    ldrb    r0, [r1, #2]              @ Pico_mcd->m.busreq
    bx      lr
m_m68k_read8_r02:
    add     r1, r1, #0x110000
    ldrb    r0, [r1, #2]
    bx      lr
m_m68k_read8_r03:
    add     r1, r1, #0x110000
    ldrb    r0, [r1, #3]
    add     r1, r1, #0x002200
    ldr     r1, [r1, #4]
    and     r0, r0, #0xc7
    tst     r1, #2                    @ DMNA pending?
    bxeq    lr
    bic     r0, r0, #1
    orr     r0, r0, #2
    bx      lr
m_m68k_read8_r04:
    add     r1, r1, #0x110000
    ldrb    r0, [r1, #4]
    bx      lr
m_m68k_read8_r06:
    ldrb    r0, [r1, #0x73]           @ IRQ vector
    bx      lr
m_m68k_read8_r07:
    ldrb    r0, [r1, #0x72]
    bx      lr
m_m68k_read8_r08:
    mov     r0, #0
    bl      Read_CDC_Host             @ TODO: make it local
    mov     r0, r0, lsr #8
    bx      lr
m_m68k_read8_r09:
    mov     r0, #0
    b       Read_CDC_Host
m_m68k_read8_r0c:
    add     r1, r1, #0x110000
    add     r1, r1, #0x002200
    ldr     r0, [r1, #0x14]           @ Pico_mcd->m.timer_stopwatch
    mov     r0, r0, lsr #24
    bx      lr
m_m68k_read8_r0d:
    add     r1, r1, #0x110000
    add     r1, r1, #0x002200
    ldr     r0, [r1, #0x14]
    mov     r0, r0, lsr #16
    bx      lr
m_m68k_read8_hi:
    cmp     r0, #0x30
    movge   r0, #0
    bxeq    lr
    add     r1, r1, #0x110000
    ldrb    r0, [r1, r0]
    bx      lr


@ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@


PicoReadM68k16_cell0:                   @ 0x220000 - 0x23ffff, cell arranged
    mov     r3, #0x0c0000
    b       0f

PicoReadM68k16_cell1:                   @ 0x220000 - 0x23ffff, cell arranged
    mov     r3, #0x0e0000
0:
    cell_map
    ldr     r1, =(Pico+0x22200)
    add     r0, r0, r3
    ldr     r1, [r1]
    bic     r0, r0, #1
    ldrh    r0, [r1, r0]
    bx      lr


PicoReadM68k16_io:
    and     r1, r0, #0xff00
    cmp     r1, #0x2000	              @ a120xx
    bne     PicoRead16_io

m_m68k_read16_m68k_regs:
    ldr     r1, =(Pico+0x22200)
    and     r0, r0, #0x3e
    ldr     r1, [r1]                  @ Pico.mcd (used everywhere)
    cmp     r0, #0x0e
    ldrlt   pc, [pc, r0, lsl #1]
    b       m_m68k_read16_hi
    .long   m_m68k_read16_r00
    .long   m_m68k_read16_r02
    .long   m_m68k_read16_r04
    .long   m_m68k_read16_r06
    .long   m_m68k_read16_r08
    .long   m_read_null               @ reserved
    .long   m_m68k_read16_r0c
m_m68k_read16_r00:
    add     r1, r1, #0x110000
    ldr     r0, [r1, #0x30]
    add     r1, r1, #0x002200
    ldrb    r1, [r1, #2]              @ Pico_mcd->m.busreq
    and     r0, r0, #0x04000000       @ we need irq2 mask state
    orr     r0, r1, r0, lsr #11
    bx      lr
m_m68k_read16_r02:
    add     r1, r1, #0x110000
    ldrb    r0, [r1, #2]
    ldrb    r2, [r1, #3]
    add     r1, r1, #0x002200
    ldr     r1, [r1, #4]
    and     r2, r2, #0xc7
    orr     r0, r2, r0, lsl #8
    tst     r1, #2                    @ DMNA pending?
    bxeq    lr
    bic     r0, r0, #1
    orr     r0, r0, #2
    bx      lr
m_m68k_read16_r04:
    add     r1, r1, #0x110000
    ldrb    r0, [r1, #4]
    mov     r0, r0, lsl #8
    bx      lr
m_m68k_read16_r06:
    ldrh    r0, [r1, #0x72]           @ IRQ vector
    bx      lr
m_m68k_read16_r08:
    mov     r0, #0
    b       Read_CDC_Host
m_m68k_read16_r0c:
    add     r1, r1, #0x110000
    add     r1, r1, #0x002200
    ldr     r0, [r1, #0x14]
    mov     r0, r0, lsr #16
    bx      lr
m_m68k_read16_hi:
    cmp     r0, #0x30
    addlt   r1, r1, #0x110000
    ldrlth  r1, [r1, r0]
    movge   r0, #0
    bxge    lr
    mov     r0, r1, lsr #8
    and     r1, r1, #0xff
    orr     r0, r0, r1, lsl #8
    bx      lr


@ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@


PicoWriteM68k8_cell0:                   @ 0x220000 - 0x23ffff, cell arranged
    mov     r12,#0x0c0000
    b       0f

PicoWriteM68k8_cell1:                   @ 0x220000 - 0x23ffff, cell arranged
    mov     r12,#0x0e0000
0:
    mov     r3, r1
    cell_map
    ldr     r2, =(Pico+0x22200)
    add     r0, r0, r12
    ldr     r2, [r2]
    eor     r0, r0, #1
    strb    r3, [r2, r0]
    bx      lr


PicoWriteM68k8_io:
    and     r2, r0, #0xff00
    cmp     r2, #0x2000                 @ a120xx?
    beq     m68k_reg_write8
    b       PicoWrite8_io


@ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@


PicoWriteM68k16_cell0:                   @ 0x220000 - 0x23ffff, cell arranged
    mov     r12, #0x0c0000
    b       0f

PicoWriteM68k16_cell1:                   @ 0x220000 - 0x23ffff, cell arranged
    mov     r12, #0x0e0000
0:
    mov     r3, r1
    cell_map
    ldr     r1, =(Pico+0x22200)
    add     r0, r0, r12
    ldr     r1, [r1]
    bic     r0, r0, #1
    strh    r3, [r1, r0]
    bx      lr


PicoWriteM68k16_io:
    and     r2, r0, #0xff00
    cmp     r2, #0x2000                 @ a120xx?
    bne     PicoWrite16_io

m_m68k_write16_regs:
    and     r0, r0, #0x3e
    cmp     r0, #0x0e
    beq     m_m68k_write16_regs_spec
    and     r3, r1, #0xff
    add     r2, r0, #1
    stmfd   sp!,{r2,r3,lr}
    mov     r1, r1, lsr #8
    bl      m68k_reg_write8
    ldmfd   sp!,{r0,r1,lr}
    b       m68k_reg_write8

m_m68k_write16_regs_spec:               @ special case
    ldr     r2, =(Pico+0x22200)
    ldr     r3, =s68k_poll_adclk
    mov     r0, #0x110000
    ldr     r2, [r2]
    add     r0, r0, #0x00000e
    mov     r1, r1, lsr #8
    strb    r1, [r2, r0]                @ if (a == 0xe) s68k_regs[0x0e] = d >> 8;
    ldr     r2, [r3]
    mov     r1, #0
    and     r2, r2, #0xfe
    cmp     r2, #0x0e
    bxne    lr
    ldr     r0, =PicoCpuCS68k
    str     r1, [r0, #0x58]             @ push s68k out of stopped state
    str     r1, [r3]
    bx      lr


@ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@                                   Sub 68k
@ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@


PicoReadS68k8_dec0:                     @ 0x080000 - 0x0bffff
    mov     r3, #0x080000               @ + ^ / 2
    b       0f

PicoReadS68k8_dec1:
    mov     r3, #0x0a0000               @ + ^ / 2
0:
    ldr     r2, =(Pico+0x22200)
    eor     r0, r0, #2
    ldr     r2, [r2]
    movs    r0, r0, lsr #1              @ +4-6 <<16
    add     r2, r2, r3                  @ map to our address
    ldrb    r0, [r2, r0]
    movcc   r0, r0, lsr #4
    andcs   r0, r0, #0xf
    bx      lr


PicoReadS68k8_pr:
    and     r2, r0, #0xfe00
    cmp     r2, #0x8000
    bne     m_s68k_read8_pcm

m_s68k_read8_regs:
    bic     r0, r0, #0xff0000
    bic     r0, r0, #0x008000
    sub     r2, r0, #0x0e
    cmp     r2, #(0x30-0x0e)
    blo     m_s68k_read8_comm
    sub     r2, r0, #0x58
    cmp     r2, #0x10
    ldrlo   r2, =gfx_cd_read
    ldrhs   r2, =s68k_reg_read16
    stmfd   sp!,{r0,lr}
    bic     r0, r0, #1
    mov     lr, pc
    bx      r2
    ldmfd   sp!,{r1,lr}
    tst     r1, #1
    moveq   r0, r0, lsr #8
    and     r0, r0, #0xff
    bx      lr

m_s68k_read8_comm:
    ldr     r1, =(Pico+0x22200)
    ldr     r1, [r1]
    add     r1, r1, #0x110000
    ldrb    r1, [r1, r0]
    b       s68k_poll_detect


m_s68k_read8_pcm:
    tst     r0, #0x8000
    bne     m_read_null

    @ must not trash r3 and r12
    ldr     r1, =(Pico+0x22200)
    bic     r0, r0, #0xff0000
@    bic     r0, r0, #0x008000
    ldr     r1, [r1]
    mov     r2, #0x110000
    orr     r2, r2, #0x002200
    cmp     r0, #0x2000
    bge     m_s68k_read8_pcm_ram
    cmp     r0, #0x20
    movlt   r0, #0
    bxlt    lr
    orr     r2, r2, #(0x48+8)           @ pcm.ch + addr_offset
    add     r1, r1, r2
    and     r2, r0, #0x1c
    ldr     r1, [r1, r2, lsl #2]
    tst     r0, #2
    moveq   r0, r1, lsr #PCM_STEP_SHIFT
    movne   r0, r1, lsr #(PCM_STEP_SHIFT+8)
    and     r0, r0, #0xff
    bx      lr

m_s68k_read8_pcm_ram:
    orr     r2, r2, #0x40
    ldr     r2, [r1, r2]
    add     r1, r1, #0x100000           @ pcm_ram
    and     r2, r2, #0x0f000000         @ bank
    add     r1, r1, r2, lsr #12
    bic     r0, r0, #0x00e000
    mov     r0, r0, lsr #1
    ldrb    r0, [r1, r0]
    bx      lr


@ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@


PicoReadS68k16_dec0:                    @ 0x080000 - 0x0bffff
    mov     r3, #0x080000               @ + ^ / 2
    b       0f

PicoReadS68k16_dec1:
    mov     r3, #0x0a0000               @ + ^ / 2
0:
    ldr     r2, =(Pico+0x22200)
    eor     r0, r0, #2
    ldr     r2, [r2]
    mov     r0, r0, lsr #1              @ +4-6 <<16
    add     r2, r2, r3                  @ map to our address
    ldrb    r0, [r2, r0]
    orr     r0, r0, r0, lsl #4
    bic     r0, r0, #0xf0
    bx      lr


PicoReadS68k16_pr:
    and     r2, r0, #0xfe00
    cmp     r2, #0x8000
    @ pcm is on 8-bit bus, would this be same as byte access?
    bne     m_s68k_read8_pcm

m_s68k_read16_regs:
    bic     r0, r0, #0xff0000
    bic     r0, r0, #0x008000
    bic     r0, r0, #0x000001
    sub     r2, r0, #0x58
    cmp     r2, #0x10
    blo     gfx_cd_read
    cmp     r0, #8
    bne     s68k_reg_read16
    mov     r0, #1
    b       Read_CDC_Host


@ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@


.macro m_s68k_write8_2M_decode
    ldr     r2, =(Pico+0x22200)
    eor     r0, r0, #2
    ldr     r2, [r2]			@ Pico.rom
    movs    r0, r0, lsr #1              @ +4-6 <<16
    add     r2, r2, r3                  @ map to our address
.endm

PicoWriteS68k8_dec_m2b0:                @ overwrite
    ands    r1, r1, #0x0f
    bxeq    lr

PicoWriteS68k8_dec_m0b0:
    mov     r3, #0x080000
    b       0f

PicoWriteS68k8_dec_m2b1:                @ overwrite
    ands    r1, r1, #0x0f
    bxeq    lr

PicoWriteS68k8_dec_m0b1:
    mov     r3, #0x0a0000
0:
    m_s68k_write8_2M_decode
    ldrb    r0, [r2, r0]!
    and     r1, r1, #0x0f
    movcc   r1, r1, lsl #4
    andcc   r3, r0, #0x0f
    andcs   r3, r0, #0xf0
    orr     r3, r3, r1
    strneb  r3, [r2]
    bx      lr

PicoWriteS68k8_dec_m1b0:                @ underwrite
    mov     r3, #0x080000
    b       0f

PicoWriteS68k8_dec_m1b1:
    mov     r3, #0x0a0000
0:
    ands    r1, r1, #0x0f
    bxeq    lr
    m_s68k_write8_2M_decode
    ldrb    r0, [r2, r0]!
    movcc   r1, r1, lsl #4
    andcc   r3, r0, #0x0f
    andcs   r3, r0, #0xf0
    teq     r3, r0
    bxne    lr
    orr     r3, r3, r1
    strneb  r3, [r2]
    bx      lr


PicoWriteS68k8_pr:
    and     r2, r0, #0xfe00
    cmp     r2, #0x8000
    bne     m_s68k_write8_pcm

m_s68k_write8_regs:
    bic     r0, r0, #0xff0000
    bic     r0, r0, #0x008000
    tst     r0, #0x7e00
    movne   r0, #0
    bxne    lr
    sub     r2, r0, #0x58
    cmp     r2, #0x10
    bhs     s68k_reg_write8
    bic     r0, r0, #1
    orr     r1, r1, r1, lsl #8
    b       gfx_cd_write16


m_s68k_write8_pcm:
    tst     r0, #0x8000
    bxne    lr
    bic     r0, r0, #0xff0000
    cmp     r0, #0x12
    movlt   r0, r0, lsr #1
    blt     pcm_write

    cmp     r0, #0x2000
    bxlt    lr

m_s68k_write8_pcm_ram:
    ldr     r3, =(Pico+0x22200)
    bic     r0, r0, #0x00e000
    ldr     r3, [r3]
    mov     r0, r0, lsr #1
    add     r2, r3, #0x110000
    add     r2, r2, #0x002200
    add     r2, r2, #0x000040
    ldr     r2, [r2]
    add     r3, r3, #0x100000           @ pcm_ram
    and     r2, r2, #0x0f000000         @ bank
    add     r3, r3, r2, lsr #12
    strb    r1, [r3, r0]
    bx      lr


@ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@


.macro m_s68k_write16_2M_decode
    ldr     r2, =(Pico+0x22200)
    eor     r0, r0, #2
    ldr     r2, [r2]
    mov     r0, r0, lsr #1              @ +4-6 <<16
    add     r2, r2, r3                  @ map to our address
.endm

PicoWriteS68k16_dec_m0b0:
    mov     r3, #0x080000
    b       0f

PicoWriteS68k16_dec_m0b1:
    mov     r3, #0x0a0000
0:
    m_s68k_write16_2M_decode
    bic     r1, r1, #0xf0
    orr     r1, r1, r1, lsr #4
    strb    r1, [r2, r0]
    bx      lr

PicoWriteS68k16_dec_m1b0:               @ underwrite
    mov     r3, #0x080000
    b       0f

PicoWriteS68k16_dec_m1b1:
    mov     r3, #0x0a0000
0:
    bics    r1, r1, #0xf000
    bicnes  r1, r1, #0x00f0
    bxeq    lr
    orr     r1, r1, r1, lsr #4
    m_s68k_write16_2M_decode
    ldrb    r0, [r2, r0]!
    and     r3, r1, #0x0f
    and     r1, r1, #0xf0
    tst     r0, #0x0f
    orreq   r0, r0, r3
    tst     r0, #0xf0
    orreq   r0, r0, r1
    strb    r0, [r2]
    bx      lr

PicoWriteS68k16_dec_m2b0:               @ overwrite
    mov     r3, #0x080000
    b       0f

PicoWriteS68k16_dec_m2b1:
    mov     r3, #0x0a0000
0:
    bics    r1, r1, #0xf000
    bicnes  r1, r1, #0x00f0
    bxeq    lr
    orr     r1, r1, r1, lsr #4
    m_s68k_write16_2M_decode
    ldrb    r0, [r2, r0]!
    ands    r3, r1, #0x0f
    andne   r0, r0, #0xf0
    orrne   r0, r0, r3
    ands    r1, r1, #0xf0
    andne   r0, r0, #0x0f
    orrne   r0, r0, r1
    strb    r0, [r2]
    bx      lr


PicoWriteS68k16_pr:
    and     r2, r0, #0xfe00
    cmp     r2, #0x8000
    bne     m_s68k_write8_pcm

m_s68k_write16_regs:
    bic     r0, r0, #0xff0000
    bic     r0, r0, #0x008000
    bic     r0, r0, #1
    tst     r0, #0x7e00
    movne   r0, #0
    bxne    lr
    cmp     r0, #0x0e
    beq     m_s68k_write16_regs_spec
    sub     r2, r0, #0x58
    cmp     r2, #0x10
    blo     gfx_cd_write16
    and     r3, r1, #0xff
    add     r2, r0, #1
    stmfd   sp!,{r2,r3,lr}
    mov     r1, r1, lsr #8
    bl      s68k_reg_write8
    ldmfd   sp!,{r0,r1,lr}
    b       s68k_reg_write8

m_s68k_write16_regs_spec:               @ special case
    ldr     r2, =(Pico+0x22200)
    mov     r0, #0x110000
    ldr     r2, [r2]
    add     r0, r0, #0x00000f
    strb    r1, [r2, r0]                @ if (a == 0xe) s68k_regs[0xf] = d;
    bx      lr

.pool

@ vim:filetype=armasm
Commit	Line	Data
	1	@*
	2	@* Memory I/O handlers for Sega/Mega CD emulation
	3	@* (C) notaz, 2007-2009
	4	@*
	5	@* This work is licensed under the terms of MAME license.
	6	@* See COPYING file in the top-level directory.
	7	@*
	8
	9	.equiv PCM_STEP_SHIFT, 11
	10
	11	.text
	12	.align 2
	13
	14	.global PicoReadM68k8_io
	15	.global PicoReadM68k16_io
	16	.global PicoWriteM68k8_io
	17	.global PicoWriteM68k16_io
	18
	19	.global PicoReadS68k8_pr
	20	.global PicoReadS68k16_pr
	21	.global PicoWriteS68k8_pr
	22	.global PicoWriteS68k16_pr
	23
	24	.global PicoReadM68k8_cell0
	25	.global PicoReadM68k8_cell1
	26	.global PicoReadM68k16_cell0
	27	.global PicoReadM68k16_cell1
	28	.global PicoWriteM68k8_cell0
	29	.global PicoWriteM68k8_cell1
	30	.global PicoWriteM68k16_cell0
	31	.global PicoWriteM68k16_cell1
	32
	33	.global PicoReadS68k8_dec0
	34	.global PicoReadS68k8_dec1
	35	.global PicoReadS68k16_dec0
	36	.global PicoReadS68k16_dec1
	37	.global PicoWriteS68k8_dec_m0b0
	38	.global PicoWriteS68k8_dec_m1b0
	39	.global PicoWriteS68k8_dec_m2b0
	40	.global PicoWriteS68k8_dec_m0b1
	41	.global PicoWriteS68k8_dec_m1b1
	42	.global PicoWriteS68k8_dec_m2b1
	43	.global PicoWriteS68k16_dec_m0b0
	44	.global PicoWriteS68k16_dec_m1b0
	45	.global PicoWriteS68k16_dec_m2b0
	46	.global PicoWriteS68k16_dec_m0b1
	47	.global PicoWriteS68k16_dec_m1b1
	48	.global PicoWriteS68k16_dec_m2b1
	49
	50	@ externs, just for reference
	51	.extern Pico
	52	.extern Read_CDC_Host
	53	.extern m68k_reg_write8
	54	.extern s68k_reg_read16
	55	.extern s68k_reg_write8
	56	.extern s68k_poll_adclk
	57	.extern s68k_poll_detect
	58	.extern gfx_cd_read
	59	.extern gfx_cd_write16
	60	.extern PicoCpuCS68k
	61	.extern PicoRead8_io
	62	.extern PicoRead16_io
	63	.extern PicoWrite8_io
	64	.extern PicoWrite16_io
	65
	66
	67	@ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
	68
	69	@ utilities
	70
	71	@ r0=addr[in,out], r1,r2=tmp
	72	.macro cell_map
	73	ands r1, r0, #0x01c000
	74	ldrne pc, [pc, r1, lsr #12]
	75	beq 0f @ most common?
	76	.long 0f
	77	.long 0f
	78	.long 0f
	79	.long 0f
	80	.long 1f
	81	.long 1f
	82	.long 2f
	83	.long 3f
	84	1: @ x16 cells
	85	and r1, r0, #0x7e00 @ col
	86	and r2, r0, #0x01fc @ row
	87	orr r2, r2, #0x0400
	88	orr r1, r2, r1, ror #13
	89	b 9f
	90	2: @ x8 cells
	91	and r1, r0, #0x3f00 @ col
	92	and r2, r0, #0x00fc @ row
	93	orr r2, r2, #0x0600
	94	orr r1, r2, r1, ror #12
	95	b 9f
	96	3: @ x4 cells
	97	and r1, r0, #0x1f80 @ col
	98	and r2, r0, #0x007c @ row
	99	orr r1, r2, r1, ror #11
	100	and r2, r0,#0x1e000
	101	orr r1, r1, r2, lsr #6
	102	b 9f
	103	0: @ x32 cells
	104	and r1, r0, #0xfc00 @ col
	105	and r2, r0, #0x03fc @ row
	106	orr r1, r2, r1, ror #14
	107	9:
	108	and r0, r0, #3
	109	orr r0, r0, r1, ror #26 @ rol 4+2
	110	.endm
	111
	112
	113	@ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
	114
	115
	116	m_read_null:
	117	mov r0, #0
	118	bx lr
	119
	120
	121	PicoReadM68k8_cell0: @ 0x220000 - 0x23ffff, cell arranged
	122	mov r3, #0x0c0000
	123	b 0f
	124
	125	PicoReadM68k8_cell1: @ 0x220000 - 0x23ffff, cell arranged
	126	mov r3, #0x0e0000
	127	0:
	128	cell_map
	129	ldr r1, =(Pico+0x22200)
	130	add r0, r0, r3
	131	ldr r1, [r1]
	132	eor r0, r0, #1
	133	ldrb r0, [r1, r0]
	134	bx lr
	135
	136
	137	PicoReadM68k8_io:
	138	and r1, r0, #0xff00
	139	cmp r1, #0x2000 @ a120xx?
	140	bne PicoRead8_io
	141
	142	ldr r1, =(Pico+0x22200)
	143	and r0, r0, #0x3f
	144	ldr r1, [r1] @ Pico.mcd (used everywhere)
	145	cmp r0, #0x0e
	146	ldrlt pc, [pc, r0, lsl #2]
	147	b m_m68k_read8_hi
	148	.long m_m68k_read8_r00
	149	.long m_m68k_read8_r01
	150	.long m_m68k_read8_r02
	151	.long m_m68k_read8_r03
	152	.long m_m68k_read8_r04
	153	.long m_read_null @ unused bits
	154	.long m_m68k_read8_r06
	155	.long m_m68k_read8_r07
	156	.long m_m68k_read8_r08
	157	.long m_m68k_read8_r09
	158	.long m_read_null @ reserved
	159	.long m_read_null
	160	.long m_m68k_read8_r0c
	161	.long m_m68k_read8_r0d
	162	m_m68k_read8_r00:
	163	add r1, r1, #0x110000
	164	ldr r0, [r1, #0x30]
	165	and r0, r0, #0x04000000 @ we need irq2 mask state
	166	mov r0, r0, lsr #19
	167	bx lr
	168	m_m68k_read8_r01:
	169	add r1, r1, #0x110000
	170	add r1, r1, #0x002200
	171	ldrb r0, [r1, #2] @ Pico_mcd->m.busreq
	172	bx lr
	173	m_m68k_read8_r02:
	174	add r1, r1, #0x110000
	175	ldrb r0, [r1, #2]
	176	bx lr
	177	m_m68k_read8_r03:
	178	add r1, r1, #0x110000
	179	ldrb r0, [r1, #3]
	180	add r1, r1, #0x002200
	181	ldr r1, [r1, #4]
	182	and r0, r0, #0xc7
	183	tst r1, #2 @ DMNA pending?
	184	bxeq lr
	185	bic r0, r0, #1
	186	orr r0, r0, #2
	187	bx lr
	188	m_m68k_read8_r04:
	189	add r1, r1, #0x110000
	190	ldrb r0, [r1, #4]
	191	bx lr
	192	m_m68k_read8_r06:
	193	ldrb r0, [r1, #0x73] @ IRQ vector
	194	bx lr
	195	m_m68k_read8_r07:
	196	ldrb r0, [r1, #0x72]
	197	bx lr
	198	m_m68k_read8_r08:
	199	mov r0, #0
	200	bl Read_CDC_Host @ TODO: make it local
	201	mov r0, r0, lsr #8
	202	bx lr
	203	m_m68k_read8_r09:
	204	mov r0, #0
	205	b Read_CDC_Host
	206	m_m68k_read8_r0c:
	207	add r1, r1, #0x110000
	208	add r1, r1, #0x002200
	209	ldr r0, [r1, #0x14] @ Pico_mcd->m.timer_stopwatch
	210	mov r0, r0, lsr #24
	211	bx lr
	212	m_m68k_read8_r0d:
	213	add r1, r1, #0x110000
	214	add r1, r1, #0x002200
	215	ldr r0, [r1, #0x14]
	216	mov r0, r0, lsr #16
	217	bx lr
	218	m_m68k_read8_hi:
	219	cmp r0, #0x30
	220	movge r0, #0
	221	bxeq lr
	222	add r1, r1, #0x110000
	223	ldrb r0, [r1, r0]
	224	bx lr
	225
	226
	227	@ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
	228
	229
	230	PicoReadM68k16_cell0: @ 0x220000 - 0x23ffff, cell arranged
	231	mov r3, #0x0c0000
	232	b 0f
	233
	234	PicoReadM68k16_cell1: @ 0x220000 - 0x23ffff, cell arranged
	235	mov r3, #0x0e0000
	236	0:
	237	cell_map
	238	ldr r1, =(Pico+0x22200)
	239	add r0, r0, r3
	240	ldr r1, [r1]
	241	bic r0, r0, #1
	242	ldrh r0, [r1, r0]
	243	bx lr
	244
	245
	246	PicoReadM68k16_io:
	247	and r1, r0, #0xff00
	248	cmp r1, #0x2000 @ a120xx
	249	bne PicoRead16_io
	250
	251	m_m68k_read16_m68k_regs:
	252	ldr r1, =(Pico+0x22200)
	253	and r0, r0, #0x3e
	254	ldr r1, [r1] @ Pico.mcd (used everywhere)
	255	cmp r0, #0x0e
	256	ldrlt pc, [pc, r0, lsl #1]
	257	b m_m68k_read16_hi
	258	.long m_m68k_read16_r00
	259	.long m_m68k_read16_r02
	260	.long m_m68k_read16_r04
	261	.long m_m68k_read16_r06
	262	.long m_m68k_read16_r08
	263	.long m_read_null @ reserved
	264	.long m_m68k_read16_r0c
	265	m_m68k_read16_r00:
	266	add r1, r1, #0x110000
	267	ldr r0, [r1, #0x30]
	268	add r1, r1, #0x002200
	269	ldrb r1, [r1, #2] @ Pico_mcd->m.busreq
	270	and r0, r0, #0x04000000 @ we need irq2 mask state
	271	orr r0, r1, r0, lsr #11
	272	bx lr
	273	m_m68k_read16_r02:
	274	add r1, r1, #0x110000
	275	ldrb r0, [r1, #2]
	276	ldrb r2, [r1, #3]
	277	add r1, r1, #0x002200
	278	ldr r1, [r1, #4]
	279	and r2, r2, #0xc7
	280	orr r0, r2, r0, lsl #8
	281	tst r1, #2 @ DMNA pending?
	282	bxeq lr
	283	bic r0, r0, #1
	284	orr r0, r0, #2
	285	bx lr
	286	m_m68k_read16_r04:
	287	add r1, r1, #0x110000
	288	ldrb r0, [r1, #4]
	289	mov r0, r0, lsl #8
	290	bx lr
	291	m_m68k_read16_r06:
	292	ldrh r0, [r1, #0x72] @ IRQ vector
	293	bx lr
	294	m_m68k_read16_r08:
	295	mov r0, #0
	296	b Read_CDC_Host
	297	m_m68k_read16_r0c:
	298	add r1, r1, #0x110000
	299	add r1, r1, #0x002200
	300	ldr r0, [r1, #0x14]
	301	mov r0, r0, lsr #16
	302	bx lr
	303	m_m68k_read16_hi:
	304	cmp r0, #0x30
	305	addlt r1, r1, #0x110000
	306	ldrlth r1, [r1, r0]
	307	movge r0, #0
	308	bxge lr
	309	mov r0, r1, lsr #8
	310	and r1, r1, #0xff
	311	orr r0, r0, r1, lsl #8
	312	bx lr
	313
	314
	315	@ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
	316
	317
	318	PicoWriteM68k8_cell0: @ 0x220000 - 0x23ffff, cell arranged
	319	mov r12,#0x0c0000
	320	b 0f
	321
	322	PicoWriteM68k8_cell1: @ 0x220000 - 0x23ffff, cell arranged
	323	mov r12,#0x0e0000
	324	0:
	325	mov r3, r1
	326	cell_map
	327	ldr r2, =(Pico+0x22200)
	328	add r0, r0, r12
	329	ldr r2, [r2]
	330	eor r0, r0, #1
	331	strb r3, [r2, r0]
	332	bx lr
	333
	334
	335	PicoWriteM68k8_io:
	336	and r2, r0, #0xff00
	337	cmp r2, #0x2000 @ a120xx?
	338	beq m68k_reg_write8
	339	b PicoWrite8_io
	340
	341
	342	@ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
	343
	344
	345	PicoWriteM68k16_cell0: @ 0x220000 - 0x23ffff, cell arranged
	346	mov r12, #0x0c0000
	347	b 0f
	348
	349	PicoWriteM68k16_cell1: @ 0x220000 - 0x23ffff, cell arranged
	350	mov r12, #0x0e0000
	351	0:
	352	mov r3, r1
	353	cell_map
	354	ldr r1, =(Pico+0x22200)
	355	add r0, r0, r12
	356	ldr r1, [r1]
	357	bic r0, r0, #1
	358	strh r3, [r1, r0]
	359	bx lr
	360
	361
	362	PicoWriteM68k16_io:
	363	and r2, r0, #0xff00
	364	cmp r2, #0x2000 @ a120xx?
	365	bne PicoWrite16_io
	366
	367	m_m68k_write16_regs:
	368	and r0, r0, #0x3e
	369	cmp r0, #0x0e
	370	beq m_m68k_write16_regs_spec
	371	and r3, r1, #0xff
	372	add r2, r0, #1
	373	stmfd sp!,{r2,r3,lr}
	374	mov r1, r1, lsr #8
	375	bl m68k_reg_write8
	376	ldmfd sp!,{r0,r1,lr}
	377	b m68k_reg_write8
	378
	379	m_m68k_write16_regs_spec: @ special case
	380	ldr r2, =(Pico+0x22200)
	381	ldr r3, =s68k_poll_adclk
	382	mov r0, #0x110000
	383	ldr r2, [r2]
	384	add r0, r0, #0x00000e
	385	mov r1, r1, lsr #8
	386	strb r1, [r2, r0] @ if (a == 0xe) s68k_regs[0x0e] = d >> 8;
	387	ldr r2, [r3]
	388	mov r1, #0
	389	and r2, r2, #0xfe
	390	cmp r2, #0x0e
	391	bxne lr
	392	ldr r0, =PicoCpuCS68k
	393	str r1, [r0, #0x58] @ push s68k out of stopped state
	394	str r1, [r3]
	395	bx lr
	396
	397
	398	@ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
	399	@ Sub 68k
	400	@ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
	401
	402
	403	PicoReadS68k8_dec0: @ 0x080000 - 0x0bffff
	404	mov r3, #0x080000 @ + ^ / 2
	405	b 0f
	406
	407	PicoReadS68k8_dec1:
	408	mov r3, #0x0a0000 @ + ^ / 2
	409	0:
	410	ldr r2, =(Pico+0x22200)
	411	eor r0, r0, #2
	412	ldr r2, [r2]
	413	movs r0, r0, lsr #1 @ +4-6 <<16
	414	add r2, r2, r3 @ map to our address
	415	ldrb r0, [r2, r0]
	416	movcc r0, r0, lsr #4
	417	andcs r0, r0, #0xf
	418	bx lr
	419
	420
	421	PicoReadS68k8_pr:
	422	and r2, r0, #0xfe00
	423	cmp r2, #0x8000
	424	bne m_s68k_read8_pcm
	425
	426	m_s68k_read8_regs:
	427	bic r0, r0, #0xff0000
	428	bic r0, r0, #0x008000
	429	sub r2, r0, #0x0e
	430	cmp r2, #(0x30-0x0e)
	431	blo m_s68k_read8_comm
	432	sub r2, r0, #0x58
	433	cmp r2, #0x10
	434	ldrlo r2, =gfx_cd_read
	435	ldrhs r2, =s68k_reg_read16
	436	stmfd sp!,{r0,lr}
	437	bic r0, r0, #1
	438	mov lr, pc
	439	bx r2
	440	ldmfd sp!,{r1,lr}
	441	tst r1, #1
	442	moveq r0, r0, lsr #8
	443	and r0, r0, #0xff
	444	bx lr
	445
	446	m_s68k_read8_comm:
	447	ldr r1, =(Pico+0x22200)
	448	ldr r1, [r1]
	449	add r1, r1, #0x110000
	450	ldrb r1, [r1, r0]
	451	b s68k_poll_detect
	452
	453
	454	m_s68k_read8_pcm:
	455	tst r0, #0x8000
	456	bne m_read_null
	457
	458	@ must not trash r3 and r12
	459	ldr r1, =(Pico+0x22200)
	460	bic r0, r0, #0xff0000
	461	@ bic r0, r0, #0x008000
	462	ldr r1, [r1]
	463	mov r2, #0x110000
	464	orr r2, r2, #0x002200
	465	cmp r0, #0x2000
	466	bge m_s68k_read8_pcm_ram
	467	cmp r0, #0x20
	468	movlt r0, #0
	469	bxlt lr
	470	orr r2, r2, #(0x48+8) @ pcm.ch + addr_offset
	471	add r1, r1, r2
	472	and r2, r0, #0x1c
	473	ldr r1, [r1, r2, lsl #2]
	474	tst r0, #2
	475	moveq r0, r1, lsr #PCM_STEP_SHIFT
	476	movne r0, r1, lsr #(PCM_STEP_SHIFT+8)
	477	and r0, r0, #0xff
	478	bx lr
	479
	480	m_s68k_read8_pcm_ram:
	481	orr r2, r2, #0x40
	482	ldr r2, [r1, r2]
	483	add r1, r1, #0x100000 @ pcm_ram
	484	and r2, r2, #0x0f000000 @ bank
	485	add r1, r1, r2, lsr #12
	486	bic r0, r0, #0x00e000
	487	mov r0, r0, lsr #1
	488	ldrb r0, [r1, r0]
	489	bx lr
	490
	491
	492	@ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
	493
	494
	495	PicoReadS68k16_dec0: @ 0x080000 - 0x0bffff
	496	mov r3, #0x080000 @ + ^ / 2
	497	b 0f
	498
	499	PicoReadS68k16_dec1:
	500	mov r3, #0x0a0000 @ + ^ / 2
	501	0:
	502	ldr r2, =(Pico+0x22200)
	503	eor r0, r0, #2
	504	ldr r2, [r2]
	505	mov r0, r0, lsr #1 @ +4-6 <<16
	506	add r2, r2, r3 @ map to our address
	507	ldrb r0, [r2, r0]
	508	orr r0, r0, r0, lsl #4
	509	bic r0, r0, #0xf0
	510	bx lr
	511
	512
	513	PicoReadS68k16_pr:
	514	and r2, r0, #0xfe00
	515	cmp r2, #0x8000
	516	@ pcm is on 8-bit bus, would this be same as byte access?
	517	bne m_s68k_read8_pcm
	518
	519	m_s68k_read16_regs:
	520	bic r0, r0, #0xff0000
	521	bic r0, r0, #0x008000
	522	bic r0, r0, #0x000001
	523	sub r2, r0, #0x58
	524	cmp r2, #0x10
	525	blo gfx_cd_read
	526	cmp r0, #8
	527	bne s68k_reg_read16
	528	mov r0, #1
	529	b Read_CDC_Host
	530
	531
	532	@ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
	533
	534
	535	.macro m_s68k_write8_2M_decode
	536	ldr r2, =(Pico+0x22200)
	537	eor r0, r0, #2
	538	ldr r2, [r2] @ Pico.rom
	539	movs r0, r0, lsr #1 @ +4-6 <<16
	540	add r2, r2, r3 @ map to our address
	541	.endm
	542
	543	PicoWriteS68k8_dec_m2b0: @ overwrite
	544	ands r1, r1, #0x0f
	545	bxeq lr
	546
	547	PicoWriteS68k8_dec_m0b0:
	548	mov r3, #0x080000
	549	b 0f
	550
	551	PicoWriteS68k8_dec_m2b1: @ overwrite
	552	ands r1, r1, #0x0f
	553	bxeq lr
	554
	555	PicoWriteS68k8_dec_m0b1:
	556	mov r3, #0x0a0000
	557	0:
	558	m_s68k_write8_2M_decode
	559	ldrb r0, [r2, r0]!
	560	and r1, r1, #0x0f
	561	movcc r1, r1, lsl #4
	562	andcc r3, r0, #0x0f
	563	andcs r3, r0, #0xf0
	564	orr r3, r3, r1
	565	strneb r3, [r2]
	566	bx lr
	567
	568	PicoWriteS68k8_dec_m1b0: @ underwrite
	569	mov r3, #0x080000
	570	b 0f
	571
	572	PicoWriteS68k8_dec_m1b1:
	573	mov r3, #0x0a0000
	574	0:
	575	ands r1, r1, #0x0f
	576	bxeq lr
	577	m_s68k_write8_2M_decode
	578	ldrb r0, [r2, r0]!
	579	movcc r1, r1, lsl #4
	580	andcc r3, r0, #0x0f
	581	andcs r3, r0, #0xf0
	582	teq r3, r0
	583	bxne lr
	584	orr r3, r3, r1
	585	strneb r3, [r2]
	586	bx lr
	587
	588
	589	PicoWriteS68k8_pr:
	590	and r2, r0, #0xfe00
	591	cmp r2, #0x8000
	592	bne m_s68k_write8_pcm
	593
	594	m_s68k_write8_regs:
	595	bic r0, r0, #0xff0000
	596	bic r0, r0, #0x008000
	597	tst r0, #0x7e00
	598	movne r0, #0
	599	bxne lr
	600	sub r2, r0, #0x58
	601	cmp r2, #0x10
	602	bhs s68k_reg_write8
	603	bic r0, r0, #1
	604	orr r1, r1, r1, lsl #8
	605	b gfx_cd_write16
	606
	607
	608	m_s68k_write8_pcm:
	609	tst r0, #0x8000
	610	bxne lr
	611	bic r0, r0, #0xff0000
	612	cmp r0, #0x12
	613	movlt r0, r0, lsr #1
	614	blt pcm_write
	615
	616	cmp r0, #0x2000
	617	bxlt lr
	618
	619	m_s68k_write8_pcm_ram:
	620	ldr r3, =(Pico+0x22200)
	621	bic r0, r0, #0x00e000
	622	ldr r3, [r3]
	623	mov r0, r0, lsr #1
	624	add r2, r3, #0x110000
	625	add r2, r2, #0x002200
	626	add r2, r2, #0x000040
	627	ldr r2, [r2]
	628	add r3, r3, #0x100000 @ pcm_ram
	629	and r2, r2, #0x0f000000 @ bank
	630	add r3, r3, r2, lsr #12
	631	strb r1, [r3, r0]
	632	bx lr
	633
	634
	635	@ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
	636
	637
	638	.macro m_s68k_write16_2M_decode
	639	ldr r2, =(Pico+0x22200)
	640	eor r0, r0, #2
	641	ldr r2, [r2]
	642	mov r0, r0, lsr #1 @ +4-6 <<16
	643	add r2, r2, r3 @ map to our address
	644	.endm
	645
	646	PicoWriteS68k16_dec_m0b0:
	647	mov r3, #0x080000
	648	b 0f
	649
	650	PicoWriteS68k16_dec_m0b1:
	651	mov r3, #0x0a0000
	652	0:
	653	m_s68k_write16_2M_decode
	654	bic r1, r1, #0xf0
	655	orr r1, r1, r1, lsr #4
	656	strb r1, [r2, r0]
	657	bx lr
	658
	659	PicoWriteS68k16_dec_m1b0: @ underwrite
	660	mov r3, #0x080000
	661	b 0f
	662
	663	PicoWriteS68k16_dec_m1b1:
	664	mov r3, #0x0a0000
	665	0:
	666	bics r1, r1, #0xf000
	667	bicnes r1, r1, #0x00f0
	668	bxeq lr
	669	orr r1, r1, r1, lsr #4
	670	m_s68k_write16_2M_decode
	671	ldrb r0, [r2, r0]!
	672	and r3, r1, #0x0f
	673	and r1, r1, #0xf0
	674	tst r0, #0x0f
	675	orreq r0, r0, r3
	676	tst r0, #0xf0
	677	orreq r0, r0, r1
	678	strb r0, [r2]
	679	bx lr
	680
	681	PicoWriteS68k16_dec_m2b0: @ overwrite
	682	mov r3, #0x080000
	683	b 0f
	684
	685	PicoWriteS68k16_dec_m2b1:
	686	mov r3, #0x0a0000
	687	0:
	688	bics r1, r1, #0xf000
	689	bicnes r1, r1, #0x00f0
	690	bxeq lr
	691	orr r1, r1, r1, lsr #4
	692	m_s68k_write16_2M_decode
	693	ldrb r0, [r2, r0]!
	694	ands r3, r1, #0x0f
	695	andne r0, r0, #0xf0
	696	orrne r0, r0, r3
	697	ands r1, r1, #0xf0
	698	andne r0, r0, #0x0f
	699	orrne r0, r0, r1
	700	strb r0, [r2]
	701	bx lr
	702
	703
	704	PicoWriteS68k16_pr:
	705	and r2, r0, #0xfe00
	706	cmp r2, #0x8000
	707	bne m_s68k_write8_pcm
	708
	709	m_s68k_write16_regs:
	710	bic r0, r0, #0xff0000
	711	bic r0, r0, #0x008000
	712	bic r0, r0, #1
	713	tst r0, #0x7e00
	714	movne r0, #0
	715	bxne lr
	716	cmp r0, #0x0e
	717	beq m_s68k_write16_regs_spec
	718	sub r2, r0, #0x58
	719	cmp r2, #0x10
	720	blo gfx_cd_write16
	721	and r3, r1, #0xff
	722	add r2, r0, #1
	723	stmfd sp!,{r2,r3,lr}
	724	mov r1, r1, lsr #8
	725	bl s68k_reg_write8
	726	ldmfd sp!,{r0,r1,lr}
	727	b s68k_reg_write8
	728
	729	m_s68k_write16_regs_spec: @ special case
	730	ldr r2, =(Pico+0x22200)
	731	mov r0, #0x110000
	732	ldr r2, [r2]
	733	add r0, r0, #0x00000f
	734	strb r1, [r2, r0] @ if (a == 0xe) s68k_regs[0xf] = d;
	735	bx lr
	736
	737	.pool
	738
	739	@ vim:filetype=armasm