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Refactor some Blinkenlights code

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This commit is contained in:
Justine Tunney 2021-03-03 13:09:06 -08:00
parent 8af91bcbe7
commit e3ee3c78e9
4 changed files with 46 additions and 40 deletions
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73
tool/build/lib/memory.c
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@ -21,6 +21,7 @@
#include "libc/log/log.h"
#include "libc/macros.internal.h"
#include "libc/mem/mem.h"
#include "libc/runtime/pc.internal.h"
#include "libc/str/str.h"
#include "libc/x/x.h"
#include "tool/build/lib/endian.h"
@ -44,50 +45,54 @@ void SetWriteAddr(struct Machine *m, int64_t addr, uint32_t size) {
}
}
long HandlePageFault(struct Machine *m, uint64_t entry, uint64_t table,
unsigned index) {
uint64_t HandlePageFault(struct Machine *m, uint64_t entry, uint64_t table,
unsigned index) {
long page;
if ((page = AllocateLinearPage(m)) != -1) {
--m->memstat.reserved;
*(uint64_t *)(m->real.p + table + index * 8) =
page | entry & ~0x7ffffffffe00;
return (*(uint64_t *)(m->real.p + table + index * 8) =
page | entry & ~0x7ffffffffe00);
} else {
return 0;
}
return page;
}
uint64_t FindPage(struct Machine *m, int64_t virt) {
uint64_t table, entry;
unsigned level, index, i;
virt &= -0x1000;
for (i = 0; i < ARRAYLEN(m->tlb); ++i) {
if (m->tlb[i].virt == virt && (m->tlb[i].entry & 1)) {
return m->tlb[i].entry;
}
}
level = 39;
entry = m->cr3;
do {
table = entry & PAGE_TA;
CHECK_LT(table, m->real.n);
index = (virt >> level) & 511;
entry = *(uint64_t *)(m->real.p + table + index * 8);
if (!(entry & 1)) return 0;
} while ((level -= 9) >= 12);
if ((entry & 0x0e00) &&
(entry = HandlePageFault(m, entry, table, index)) == -1) {
return 0;
}
m->tlbindex = (m->tlbindex + 1) & (ARRAYLEN(m->tlb) - 1);
m->tlb[m->tlbindex] = m->tlb[0];
m->tlb[0].virt = virt;
m->tlb[0].entry = entry;
return entry;
}
void *FindReal(struct Machine *m, int64_t virt) {
long page;
uint64_t table, entry;
uint64_t table, entry, page;
unsigned skew, level, index, i;
if ((m->mode & 3) != XED_MODE_REAL) {
if (-0x800000000000 <= virt && virt < 0x800000000000) {
skew = virt & 0xfff;
virt &= -0x1000;
for (i = 0; i < ARRAYLEN(m->tlb); ++i) {
if (m->tlb[i].virt == virt && m->tlb[i].host) {
return m->tlb[i].host + skew;
}
}
level = 39;
entry = m->cr3;
do {
table = entry & 0x7ffffffff000;
CHECK_LT(table, m->real.n);
index = (virt >> level) & 511;
entry = *(uint64_t *)(m->real.p + table + index * 8);
if (!(entry & 1)) return NULL;
} while ((level -= 9) >= 12);
if (!(entry & 0x0e00)) {
page = entry & 0x7ffffffff000;
CHECK_LT(page, m->real.n);
} else if ((page = HandlePageFault(m, entry, table, index)) == -1) {
return NULL;
}
m->tlbindex = (m->tlbindex + 1) & (ARRAYLEN(m->tlb) - 1);
m->tlb[m->tlbindex] = m->tlb[0];
m->tlb[0].virt = virt;
m->tlb[0].host = m->real.p + page;
return m->real.p + page + skew;
if (!(entry = FindPage(m, virt))) return NULL;
return m->real.p + (entry & PAGE_TA) + (virt & 0xfff);
} else {
return NULL;
}