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oot/asm/osInvalDCache.s
Tharo 7334ffa373
Improve the state of handwritten assembly files (#865)
* Format all handwritten asm and document some

* Use c preprocessor for constants

* Fix

* Fix PI_STATUS_ERROR, some label improvements

* Avoid hi/lo for constants

* Some more comments

* Properly mark functions as functions and their sizes

* Fix merge

* Improvements

* Review suggestions, rework procedure start/end macros to be more like libreultra

* Move IPL3 symbol definitions into ipl3.s

* Fix undefined_syms, add include and language guards to asm.h and fix the comment in gbi.h

* Consistent hex capitalization, add some MIPS builtin defines to CC_CHECK to behave properly

* Add -no-pad-sections assembler option and clean up alignment in gu files and bzero

* Further suggestions and improvements

* Matrix conversion function clarifications

* Fix passing AVOID_UB to gcc

* Suggestions

* Suggestions, global interrupt mask improvements

* Further suggestions, interrupt mask comments

* Comments fixes, rdb.h

* Switch from # comments to // comments, remove unnecesary .set gp=64 directives

* Further review suggestions

* Missed one
2022-05-01 01:03:22 +02:00

94 lines
2.6 KiB
ArmAsm

#include "ultra64/asm.h"
#include "ultra64/r4300.h"
.set noat
.set noreorder
.section .text
.balign 16
/**
* void osInvalDCache(void* vaddr, s32 nbytes);
*
* Invalidates the CPU Data Cache for `nbytes` at `vaddr`.
* The cache is not automatically synced with physical memory, so cache
* lines must be invalidated to ensure old data is not used in place of
* newly available data supplied by an external agent in a DMA operation.
*
* If `vaddr` is not aligned to a cache line boundary, or nbytes is not a
* multiple of the data cache line size (16 bytes) a larger region is
* invalidated.
*
* If the amount to invalidate is at least the data cache size (DCACHE_SIZE),
* the entire data cache is invalidated.
*/
LEAF(osInvalDCache)
// If the amount to invalidate is less than or equal to 0, return immediately
blez $a1, 3f
nop
// If the amount to invalidate is as large as or larger than
// the data cache size, invalidate all
li $t3, DCACHE_SIZE
sltu $at, $a1, $t3
beqz $at, 4f
nop
// Ensure end address doesn't wrap around and end up smaller
// than the start address
move $t0, $a0
addu $t1, $a0, $a1
sltu $at, $t0, $t1
beqz $at, 3f
nop
// Mask start with cache line
andi $t2, $t0, DCACHE_LINEMASK
// If mask is not zero, the start is not cache aligned
beqz $t2, 1f
addiu $t1, $t1, -DCACHE_LINESIZE
// Subtract mask result to align to cache line
subu $t0, $t0, $t2
// Hit-Writeback-Invalidate unaligned part
cache (CACH_PD | C_HWBINV), ($t0)
sltu $at, $t0, $t1
// If that's all there is to do, return early
beqz $at, 3f
nop
addiu $t0, $t0, DCACHE_LINESIZE
1:
// Mask end with cache line
andi $t2, $t1, DCACHE_LINEMASK
// If mask is not zero, the end is not cache aligned
beqz $t2, 1f
nop
// Subtract mask result to align to cache line
subu $t1, $t1, $t2
// Hit-Writeback-Invalidate unaligned part
cache (CACH_PD | C_HWBINV), DCACHE_LINESIZE($t1)
sltu $at, $t1, $t0
// If that's all there is to do, return early
bnez $at, 3f
nop
// Invalidate the rest
1:
// Hit-Invalidate
cache (CACH_PD | C_HINV), ($t0)
sltu $at, $t0, $t1
bnez $at, 1b
addiu $t0, $t0, DCACHE_LINESIZE
3:
jr $ra
nop
4:
li $t0, K0BASE
addu $t1, $t0, $t3
addiu $t1, $t1, -DCACHE_LINESIZE
5:
// Index-Writeback-Invalidate
cache (CACH_PD | C_IWBINV), ($t0)
sltu $at, $t0, $t1
bnez $at, 5b
addiu $t0, DCACHE_LINESIZE
jr $ra
nop
END(osInvalDCache)