homebrew/debug.asm

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NASM
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// debug routines for the 64drive, not a real devcart!
Drive64Write:
// a0: RAM address to copy from
// a1: length of data to copy in bytes
// v0: error code (0 is OK)
// TODO: a0 should be double-word aligned if used directly with DMA
// assert a0 (RAM address) is word-aligned
andi t9, a0, 3
bnezl t9, Drive64WriteExit
lli v0, 1
// assert a1 (copy length) is word-aligned
andi t9, a1, 3
bnezl t9, Drive64WriteExit
lli v0, 2
blez a1, Drive64WriteExit // nothing to write? nothing to do!
lli v0, 0 // delay slot
lui a2, 0x103F // SDRAM destination
move a3, a1 // SDRAM length
// flush the cache at a0 to RAM before doing any DMA
andi t6, a0, 0xF
addu t7, a0, a1 // stop flushing around here
subu t6, a0, t6 // align a0 to data line
-
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cache 1, 0(t6) // data cache Index Writeback Invalidate
addiu t6, 0x10 // (delay slot) += data line size
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sltu at, t6, t7
bnez at,-
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nop
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// AND off the DRAM address
li t9, 0x007FFFFF // __osPiRawStartDma uses 0x1FFFFFFF?
and t1, a0, t9
// cart address
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or t2, a2, r0
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// set length (needs to be decremented due to DMA quirk)
subiu t3, a3, 1
PI_WAIT()
sw t1, PI_DRAM_ADDR(t5)
sw t2, PI_CART_ADDR(t5)
sw t3, PI_RD_LEN(t5) // "read" from DRAM to cart
// PI_WAIT() // if we always wait before doing operations, this shouldn't be necessary
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Drive64WriteDirect: // TODO: rewrite so this takes a0,a1 instead of a2,a3
lli v0, 0
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lui at, 0x0100 // set printf channel
or a3, a3, at
lli t1, 0x08 // WRITE mode
// SDRAM parameter is given in multiples of halfwords
li t9, 0x0FFFFFFF
and a2, a2, t9
srl a2, a2, 1
lui t9, K_BASE
lw t9, K_CI_BASE(t9)
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CI_USB_WRITE_WAIT(0x10000) // clobbers t0,v0, requires t9
bnez v0, Drive64WriteExit
nop
sw a2, CI_USB_PARAM_RESULT_0(t9)
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PI_WAIT() // yes, these waits seem to be necessary
sw a3, CI_USB_PARAM_RESULT_1(t9)
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PI_WAIT()
sw t1, CI_USB_COMMAND_STATUS(t9)
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CI_USB_WRITE_WAIT(0x10000) // clobbers t0,v0, requires t9
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Drive64WriteExit:
jr ra
nop
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Drive64TestWrite:
li a2, 0xA0000020
lli a3, 0x20
j Drive64WriteDirect
nop
include "xxd.asm"
DumpAndWrite:
// a0: source address
// a1: source length
// a2: temp string address
// a3: temp string maximum length
// v0: error code (0 is OK)
subiu sp, sp, 0x20
sw ra, 0x10(sp)
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// TODO: can i just use the a0,a1,a2,a3 slots here?
sw s0, 0x14(sp)
sw s1, 0x18(sp)
or s0, a2, r0
jal xxd
or s1, a3, r0
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// v0 passthru
bnez v0, DumpAndWriteExit
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lui t0, K_BASE // delay slot
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lw t1, K_CONSOLE_AVAILABLE(t0)
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beqz t1, DumpAndWriteExit
ori a0, s0, r0 // delay slot
jal Drive64Write
ori a1, s1, r0
// v0 passthru
DumpAndWriteExit:
lw ra, 0x10(sp)
lw s0, 0x14(sp)
lw s1, 0x18(sp)
jr ra
addiu sp, sp, 0x20