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Code Issues Releases Wiki Activity

Fiddling with DEIM/DSTS interctions

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This commit is contained in:
Ross Wilson 2018-08-04 22:40:31 +07:00
parent 0139097a94
commit 253ec3eeff
2 changed files with 40 additions and 15 deletions
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51
vimlac/dcpu.c
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@ -18,11 +18,12 @@
* Constants, etc.
******/
#define MSBBITS 6
#define LSBBITS 5
//#define MSBBITS 6
//#define LSBBITS 5
#define LSBBITS 4
#define MSBMASK 03740
#define LSBMASK 037
#define MSBMASK 0x7f0
#define LSBMASK 0x0f
// full 11 bits of display addressing
#define DMASK 03777
@ -130,7 +131,8 @@ DEIMdecode(BYTE byte)
// now decode the DEIM byte
if (byte & 0x80)
{
if (byte & 0x40)
// increment byte decoding
if (byte & 0x40) // beam on/off bit
{
strcat(bptr, "B");
*++bptr = '\0';
@ -141,26 +143,27 @@ DEIMdecode(BYTE byte)
*++bptr = '\0';
}
if (byte & 0x20)
if (byte & 0x20) // increment/decrement X
{
strcat(bptr, "-");
*++bptr = '\0';
}
sprintf(bptr, "%d", (byte >> 3) & 0x03);
sprintf(bptr, "%d", (byte >> 3) & 0x03); // magnitude X movement
bptr = DEIM_result + strlen(DEIM_result);
if (byte & 0x04)
if (byte & 0x04) // increment/decrement Y
{
strcat(bptr, "-");
*++bptr = '\0';
}
sprintf(bptr, "%d", byte & 0x03);
bptr = DEIM_result + strlen(DEIM_result);
bptr = DEIM_result + strlen(DEIM_result); // magnitude Y movement
}
else
{
// control byte decoding
if (byte == 0111)
{
strcat(bptr, "N");
@ -205,8 +208,11 @@ char *doDEIMByte(BYTE byte, bool last)
{
char *trace = DEIMdecode(byte);
if (byte & 0x80) // increment mode
vlog("doDEIMByte: DX=%04x, DY=%04x,", DX, DY);
if (byte & 0x80)
{
// increment mode
int dx = (byte & 0x18) >> 3; // extract X/Y deltas
int dy = (byte & 0x03);
@ -231,13 +237,18 @@ char *doDEIMByte(BYTE byte, bool last)
DY += dy * DScale;
}
// ensure dislay X/Y in limits
DX &= DMASK;
DY &= DMASK;
if (byte & 0x40) // if beam on
{
display_draw(prevDX, prevDY, DX, DY);
}
}
else // control instructions
else
{
// control instructions
if (byte & 0x40) // escape DEIM mode
{
Mode = MODE_NORMAL;
@ -255,22 +266,32 @@ char *doDEIMByte(BYTE byte, bool last)
if (byte & 0x10) // inc X MSB
{
vlog("before inc X MSB, X=%04x", DX);
DX += (1 << LSBBITS);
DX &= DMASK;
vlog(" after inc X MSB, X=%04x", DX);
}
if (byte & 0x08) // clear X LSB
{
vlog("before clear X LSB, X=%04x", DX);
DX &= MSBMASK;
vlog(" after clear X LSB, X=%04x", DX);
}
if (byte & 0x02) // inc Y MSB
{
vlog("before inc Y MSB, Y=%04x", DY);
DY += (1 << LSBBITS);
DY &= DMASK;
vlog(" after inc Y MSB, Y=%04x", DY);
}
if (byte & 0x01) // clear Y LSB
{
vlog("before clear Y LSB, Y=%04x", DY);
DY &= MSBMASK;
vlog(" after clear Y LSB, Y=%04x", DY);
}
}
@ -288,7 +309,8 @@ Description : The emulated display CPU instructions.
static
int i_DDXM(void)
{
DX -= 040;
DX -= 02000;
DX &= DMASK;
trace_dcpu("DDXM");
return 1;
}
@ -296,7 +318,8 @@ int i_DDXM(void)
static
int i_DDYM(void)
{
DY -= 040;
DY -= 02000;
DY &= DMASK;
trace_dcpu("DDYM");
return 1;
}
@ -329,6 +352,7 @@ static
int i_DIXM(void)
{
DX += 04000;
DX &= DMASK;
trace_dcpu("DIXM");
return 1;
}
@ -337,6 +361,7 @@ static
int i_DIYM(void)
{
DY += 04000;
DY &= DMASK;
trace_dcpu("DIYM");
return 1;
}

4
vimlac/display_sdl.c
View File

@ -20,8 +20,8 @@
// screen/display stuff
#define MAX_X 512 // max X coord for display
#define MAX_Y 512 // max Y coord for display
#define SCALE_MAX_X 1024 // max vimlac X coord
#define SCALE_MAX_Y 1024 // max vimlac Y coord
#define SCALE_MAX_X 512 // max vimlac X coord
#define SCALE_MAX_Y 512 // max vimlac Y coord
//#define SCALE_MAX_X 2048 // max vimlac X coord
//#define SCALE_MAX_Y 2048 // max vimlac Y coord