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Imlac: Model X/Y MSB and LSB.

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This commit is contained in:
Lars Brinkhoff
2025-06-02 12:57:07 +02:00
committed by Mark Pizzolato
parent 1c792f8309
commit 8e0b432f1a
1 changed files with 50 additions and 29 deletions
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79
imlac/imlac_dp.c
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@@ -35,7 +35,8 @@ static uint16 SP = 0;
static uint16 ON = 0; static uint16 ON = 0;
static uint16 HALT = 0; static uint16 HALT = 0;
static uint16 MODE = 0; static uint16 MODE = 0;
static uint16 XA, YA; static uint16 XMSB, YMSB;
static uint16 XLSB, YLSB;
static uint16 SCALE = 2; static uint16 SCALE = 2;
static uint16 BLOCK = 0; static uint16 BLOCK = 0;
static uint16 MIT8K; static uint16 MIT8K;
@@ -67,8 +68,8 @@ static REG dp_reg[] = {
{ ORDATAD (MODE, MODE, 1, "Display mode") }, { ORDATAD (MODE, MODE, 1, "Display mode") },
{ BRDATAD (DT, DT, 8, 16, 8, "Return address stack") }, { BRDATAD (DT, DT, 8, 16, 8, "Return address stack") },
{ ORDATAD (SP, SP, 3, "Stack pointer") }, { ORDATAD (SP, SP, 3, "Stack pointer") },
{ ORDATAD (XA, XA, 11, "X accumulator") }, { ORDATAD (XMSB, XMSB, 11, "X accumulator") },
{ ORDATAD (YA, YA, 11, "Y accumulator") }, { ORDATAD (YMSB, YMSB, 11, "Y accumulator") },
{ ORDATAD (SCALE, SCALE, 3, "Scale") }, { ORDATAD (SCALE, SCALE, 3, "Scale") },
{ ORDATAD (BLOCK, BLOCK, 3, "Block") }, { ORDATAD (BLOCK, BLOCK, 3, "Block") },
{ ORDATAD (MIT8K, MIT8K, 1, "MIT 8K addressing") }, { ORDATAD (MIT8K, MIT8K, 1, "MIT 8K addressing") },
@@ -165,6 +166,25 @@ dp_iot (uint16 insn, uint16 AC)
return AC; return AC;
} }
static uint16 deflect (uint16 msb, uint16 lsb)
{
return (msb << 5) + lsb;
}
static void increment (uint16 *msb, uint16 *lsb, uint16 x)
{
*lsb += SCALE * x;
*msb += *lsb >> 5;
*lsb &= 037;
}
static void decrement (uint16 *msb, uint16 *lsb, uint16 x)
{
*lsb -= SCALE * x;
*msb += ((int16)*lsb) >> 5;
*lsb &= 037;
}
static t_stat static t_stat
dp_opr(uint16 insn) dp_opr(uint16 insn)
{ {
@@ -202,7 +222,7 @@ dp_opr(uint16 insn)
} }
if (insn & 00020) { /* DDSP */ if (insn & 00020) { /* DDSP */
sim_debug (DBG, &dp_dev, "DDSP "); sim_debug (DBG, &dp_dev, "DDSP ");
crt_point (XA, YA); crt_point (deflect (XMSB, XLSB), deflect (YMSB, YLSB));
} }
if (insn & 00040) { /* DRJM */ if (insn & 00040) { /* DRJM */
sim_debug (DBG, &dp_dev, "DRJM "); sim_debug (DBG, &dp_dev, "DRJM ");
@@ -213,19 +233,19 @@ dp_opr(uint16 insn)
} }
if (insn & 00100) { /* DDYM */ if (insn & 00100) { /* DDYM */
sim_debug (DBG, &dp_dev, "DDYM "); sim_debug (DBG, &dp_dev, "DDYM ");
YA -= 040; YMSB--;
} }
if (insn & 00200) { /* DDXM */ if (insn & 00200) { /* DDXM */
sim_debug (DBG, &dp_dev, "DDXM "); sim_debug (DBG, &dp_dev, "DDXM ");
XA -= 040; XMSB--;
} }
if (insn & 00400) { /* DIYM */ if (insn & 00400) { /* DIYM */
sim_debug (DBG, &dp_dev, "DIYM "); sim_debug (DBG, &dp_dev, "DIYM ");
YA += 040; YMSB++;
} }
if (insn & 01000) { /* DIXM */ if (insn & 01000) { /* DIXM */
sim_debug (DBG, &dp_dev, "DIXM "); sim_debug (DBG, &dp_dev, "DIXM ");
XA += 040; XMSB++;
} }
if (insn & 02000) { /* DHVC */ if (insn & 02000) { /* DHVC */
sim_debug (DBG, &dp_dev, "DHVC "); sim_debug (DBG, &dp_dev, "DHVC ");
@@ -294,7 +314,7 @@ dp_opt (uint16 insn)
static void static void
dp_inc_vector (uint16 byte) dp_inc_vector (uint16 byte)
{ {
uint16 x1 = XA, y1 = YA; uint16 x1 = deflect (XMSB, XLSB), y1 = deflect (YMSB, YLSB);
uint16 dx, dy; uint16 dx, dy;
if (byte == 0200) { if (byte == 0200) {
@@ -309,19 +329,18 @@ dp_inc_vector (uint16 byte)
sim_debug (DBG, &dp_dev, "%o", byte & 3); sim_debug (DBG, &dp_dev, "%o", byte & 3);
} }
dx = SCALE * ((byte >> 3) & 3); dx = (byte >> 3) & 3;
dy = SCALE * (byte & 3); dy = byte & 3;
if (byte & 040) if (byte & 040)
XA -= dx; decrement (&XMSB, &XLSB, dx);
else else
XA += dx; increment (&XMSB, &XLSB, dx);
if (byte & 4) if (byte & 4)
YA -= dy; decrement (&YMSB, &YLSB, dy);
else else
YA += dy; increment (&YMSB, &YLSB, dy);
if (byte & 0100) if (byte & 0100)
crt_line (x1, y1, XA, YA); crt_line (x1, y1, deflect (XMSB, XLSB), deflect (YMSB, YLSB));
} }
static void static void
@@ -345,15 +364,15 @@ dp_inc_escape (uint16 byte)
sim_debug (DBG, &dp_dev, "stack underflow"); sim_debug (DBG, &dp_dev, "stack underflow");
} }
if (byte & 020) if (byte & 020)
XA += 040; XMSB++;
if (byte & 010) if (byte & 010)
XA &= 03740; XLSB = 0;
if (byte & 4) /* Enter PPM mode. */ if (byte & 4) /* Enter PPM mode. */
; ;
if (byte & 2) if (byte & 2)
YA += 040; YMSB++;
if (byte & 1) if (byte & 1)
YA &= 03740; YLSB = 0;
} }
static void static void
@@ -380,7 +399,7 @@ dp_deim (uint16 insn)
static void static void
dp_dlvh (uint16 insn1, uint16 insn2, uint16 insn3) dp_dlvh (uint16 insn1, uint16 insn2, uint16 insn3)
{ {
uint16 x1 = XA, y1 = YA; uint16 x1 = deflect (XMSB, XLSB), y1 = deflect (YMSB, YLSB);
uint16 m, n, dx, dy; uint16 m, n, dx, dy;
m = insn2 & 07777; m = insn2 & 07777;
n = insn3 & 07777; n = insn3 & 07777;
@@ -392,15 +411,15 @@ dp_dlvh (uint16 insn1, uint16 insn2, uint16 insn3)
dy = n; dy = n;
} }
if (insn3 & 040000) if (insn3 & 040000)
XA -= SCALE * dx; decrement (&XMSB, &XLSB, dx);
else else
XA += SCALE * dx; increment (&XMSB, &XLSB, dx);
if (insn3 & 020000) if (insn3 & 020000)
YA -= SCALE * dy; decrement (&YMSB, &YLSB, dy);
else else
YA += SCALE * dy; increment (&YMSB, &YLSB, dy);
if (insn2 & 020000) if (insn2 & 020000)
crt_line (x1, y1, XA, YA); crt_line (x1, y1, deflect (XMSB, XLSB), deflect (YMSB, YLSB));
} }
static void static void
@@ -412,11 +431,13 @@ dp_insn (uint16 insn)
break; break;
case 1: /* DLXA */ case 1: /* DLXA */
sim_debug (DBG, &dp_dev, "DLXA\n"); sim_debug (DBG, &dp_dev, "DLXA\n");
XA = (insn & 01777) << 1; XMSB = (insn >> 4) & 0077;
XLSB = (insn << 1) & 0036;
break; break;
case 2: /* DLYA */ case 2: /* DLYA */
sim_debug (DBG, &dp_dev, "DLYA\n"); sim_debug (DBG, &dp_dev, "DLYA\n");
YA = (insn & 01777) << 1; YMSB = (insn >> 4) & 0077;
YLSB = (insn << 1) & 0036;
break; break;
case 3: /* DEIM */ case 3: /* DEIM */
sim_debug (DBG, &dp_dev, "DEIM "); sim_debug (DBG, &dp_dev, "DEIM ");