iris/riscv-linux-heap
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ok I need to actually do school work

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This commit is contained in:
Bryan McShea
2022-10-11 21:02:17 -04:00
parent 0eaf127edd
commit 1c6dc303b8
3 changed files with 74 additions and 30 deletions
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src/lib/heap.s
+20 -19
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@@ -7,7 +7,7 @@
.equ align_imask, 0b111
.equ align_mask, ~align_imask
.equ used_mask, 0b001
.equ prev_used, 0b001
.equ size_mask, align_mask
# block node
@@ -36,14 +36,16 @@ heap_oom:
.section .data
.align 4
.equ heap_start, 0
.equ heap_first_free, 8 # matches fb_next
.equ heap_end, 16
.global heap_info # for testing only
.global heap_info # global for testing only
.equ heap_last_used, 0 # last free block will set this
.equ heap_first_free, 8 # matches fb_next
.equ heap_start, 16
.equ heap_end, 24
heap_info:
.dword __global_pointer$
.dword 0
.dword 0
.dword __global_pointer$
.dword 0
@@ -72,23 +74,23 @@ heap_init:
li a0, 0
jal brk
andi a0, a0, align_mask
sub t2, a0, t1 # size = end - start (t2)
sub t2, a0, t1 # size = end - start (t2)
li t3, sizeof_fb
bgeu t2, t3, 0f # check if enough mem to start
bgeu t2, t3, 0f # check if enough mem to start
move a1, a0
add a0, t1, t3
jal brk_or_panic # if not, get more
sub t2, a0, t1 # recalc size (t2)
jal brk_or_panic # if not, get more
sub t2, a0, t1 # recalc size (t2)
0:
sd a0, heap_end(t0)
# create initial free block
ori t2, t2, 0x1 # add prev used
sd t2, bsize(t1) # store size
sd t0, fb_next(t1) # store next
sd t1, -8(a0) # store addr at end
ori t2, t2, prev_used # add prev used
sd t2, bsize(t1) # store size
sd t0, fb_next(t1) # store next
sd t1, -8(a0) # store addr at end
sd t1, heap_first_free(t0)
@@ -149,10 +151,9 @@ heap_alloc:
jal brk_or_panic # set heap end (a0)
sd a0, heap_end(t3) # update end in info
sub t2, a0, t1 # new free space (t2)
andi t5, t2, 1 # prev used bit
andi t5, t2, prev_used # prev used bit
sd t5, bsize(t1) # update size
sd t3, fb_next(t1) # update next (for case 3)
0:
# deal with extra free space
@@ -165,7 +166,7 @@ heap_alloc:
sd t3, fb_next(t6) # set prev block next to new
add t6, t3, t5 # store addr at end
sd t3, -8(t6)
ori t6, t5, 1 # store size with prev in use
ori t6, t5, prev_used # store size with prev in use
sd t6, bsize(t3)
ld t6, fb_next(t1) # copy next
sd t6, fb_next(t3)
@@ -178,14 +179,14 @@ heap_alloc:
add t3, t1, t0
beq t3, t4, 1f # if this is not at the end
ld t4, bsize(t3) # set next's prev used to 1
ori t4, t4, 1
ori t4, t4, prev_used
sd t4, bsize(t3)
1:
# create used block
add t2, t0, t1 # end of block
ori t0, t0, 1 # prev used bit
ori t0, t0, prev_used # prev used bit
sd t0, bsize(t1) # store size
sd zero, fb_next(t1) # remove free block stuff
sd zero, -8(t2)