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unittester: Implement 0x03 "Verify Screen Snapshot Rectangle"

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Basic quick tests show that this is probably consistent with command 0x02.
This commit is contained in:
GreaseMonkey
2024-01-08 12:07:14 +13:00
parent f35dd20974
commit 30aacb2a1a
2 changed files with 58 additions and 25 deletions
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4
doc/specifications/86box-unit-tester.md
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@@ -49,8 +49,6 @@ Set the I/O base address to 0xFFFF using the above method.
### Executing commands
**TODO: IMPLEMENT ME!**
The ports at IOBASE+0x00 and IOBASE+0x01 are all 8 bits wide.
Writing to IOBASE+0x00 cancels any in-flight commands and sends a new command.
@@ -145,8 +143,6 @@ Output:
### 0x03: Verify Screen Snapshot Rectangle
**TODO: IMPLEMENT ME!**
As per 0x02 "Read Screen Snapshot Rectangle", except instead of returning the pixel data, it returns a CRC-32 of the data.
The CRC is as per zlib's `crc32()` function. Specifically, one uses a right-shifting Galois LFSR with a polynomial of 0xEDB88320, bytes XORed against the least significant byte, the initial seed is 0xFFFFFFFF, and all bits of the output are inverted.

79
src/device/unittester.c
View File

@@ -97,6 +97,7 @@ struct unittester_state {
uint16_t read_snap_height;
int16_t read_snap_xoffs;
int16_t read_snap_yoffs;
uint32_t read_snap_crc;
/* 0x04: Exit */
uint8_t exit_code;
@@ -138,6 +139,25 @@ unittester_log(const char *fmt, ...)
# define unittester_log(fmt, ...)
#endif
static uint8_t
unittester_read_snap_rect_idx(uint32_t offs)
{
/* WARNING: If the width is somehow 0 and wasn't caught earlier, you'll probably get a divide by zero crash. */
uint32_t idx = (offs & 0x3);
int32_t x = (offs >> 2) % unittester.read_snap_width;
int32_t y = (offs >> 2) / unittester.read_snap_width;
x += unittester.read_snap_xoffs;
y += unittester.read_snap_yoffs;
if (x < 0 || y < 0 || x >= unittester.snap_overscan_width || y >= unittester.snap_overscan_height) {
/* Out of range! */
return (idx == 3 ? 0xFF : 0x00);
} else {
/* In range */
return (unittester_screen_buffer->line[y][x] & 0x00FFFFFF)>>(idx*8);
}
}
static void
unittester_write(uint16_t port, uint8_t val, UNUSED(void *priv))
{
@@ -171,6 +191,13 @@ unittester_write(uint16_t port, uint8_t val, UNUSED(void *priv))
unittester.write_len = 8;
break;
/* 0x03: Verify Screen Snapshot Rectangle */
case UT_CMD_VERIFY_SCREEN_SNAPSHOT_RECTANGLE:
unittester.cmd_id = UT_CMD_VERIFY_SCREEN_SNAPSHOT_RECTANGLE;
unittester.status = UT_STATUS_AWAITING_WRITE;
unittester.write_len = 8;
break;
/* 0x04: Exit */
case UT_CMD_EXIT:
unittester.cmd_id = UT_CMD_EXIT;
@@ -215,6 +242,7 @@ unittester_write(uint16_t port, uint8_t val, UNUSED(void *priv))
break;
case UT_CMD_READ_SCREEN_SNAPSHOT_RECTANGLE:
case UT_CMD_VERIFY_SCREEN_SNAPSHOT_RECTANGLE:
switch(unittester.write_offs) {
case 0:
unittester.read_snap_width = (uint16_t)val;
@@ -322,6 +350,7 @@ unittester_write(uint16_t port, uint8_t val, UNUSED(void *priv))
break;
case UT_CMD_READ_SCREEN_SNAPSHOT_RECTANGLE:
case UT_CMD_VERIFY_SCREEN_SNAPSHOT_RECTANGLE:
/* Offset the X,Y offsets by the overscan offsets. */
unittester.read_snap_xoffs += (int16_t)unittester.snap_img_xoffs;
unittester.read_snap_yoffs += (int16_t)unittester.snap_img_yoffs;
@@ -335,15 +364,34 @@ unittester_write(uint16_t port, uint8_t val, UNUSED(void *priv))
If there is any need to fix this bug... then go and make the variables 64-bit :P
*/
unittester.read_len = ((uint32_t)unittester.read_snap_width) * ((uint32_t)unittester.read_snap_height) * 4;
unittester.read_snap_crc = 0xFFFFFFFF;
/* Do we have anything to read? */
if (unittester.read_len >= 1) {
/* Yes - start reads! */
if (unittester.cmd_id == UT_CMD_VERIFY_SCREEN_SNAPSHOT_RECTANGLE) {
/* Read everything and compute CRC */
uint32_t crc = 0xFFFFFFFF;
for (uint32_t i = 0; i < unittester.read_len; i++) {
crc ^= 0xFF & (uint32_t)unittester_read_snap_rect_idx(i);
/* Use some bit twiddling until we have a table-based fast CRC-32 implementation */
for (uint32_t j = 0; j < 8; j++) {
crc = (crc >> 1) ^ ((-(crc&0x1)) & 0xEDB88320);
}
}
unittester.read_snap_crc = crc ^ 0xFFFFFFFF;
/* Set actual read length for CRC result */
unittester.read_len = 4;
unittester.status = UT_STATUS_AWAITING_READ;
} else {
/* No - stop here. */
unittester.cmd_id = UT_CMD_NOOP;
unittester.status = UT_STATUS_IDLE;
/* Do we have anything to read? */
if (unittester.read_len >= 1) {
/* Yes - start reads! */
unittester.status = UT_STATUS_AWAITING_READ;
} else {
/* No - stop here. */
unittester.cmd_id = UT_CMD_NOOP;
unittester.status = UT_STATUS_IDLE;
}
}
break;
@@ -422,22 +470,11 @@ unittester_read(uint16_t port, UNUSED(void *priv))
break;
case UT_CMD_READ_SCREEN_SNAPSHOT_RECTANGLE:
/* WARNING: If the width is somehow 0 and wasn't caught earlier, you'll probably get a divide by zero crash. */
{
uint32_t idx = unittester.read_offs & 0x3;
int32_t x = (unittester.read_offs >> 2) % unittester.read_snap_width;
int32_t y = (unittester.read_offs >> 2) / unittester.read_snap_width;
x += unittester.read_snap_xoffs;
y += unittester.read_snap_yoffs;
outval = unittester_read_snap_rect_idx(unittester.read_offs);
break;
if (x < 0 || y < 0 || x >= unittester.snap_overscan_width || y >= unittester.snap_overscan_height) {
/* Out of range! */
outval = (idx == 3 ? 0xFF : 0x00);
} else {
/* In range */
outval = (unittester_screen_buffer->line[y][x] & 0x00FFFFFF)>>(idx*8);
}
}
case UT_CMD_VERIFY_SCREEN_SNAPSHOT_RECTANGLE:
outval = (uint8_t)(unittester.read_snap_crc >> (8*unittester.read_offs));
break;
/* This should not be reachable, but just in case... */