(RV64 Only) 32-bit Parallel Multiply & Add Instructions

__STATIC_FORCEINLINE long __RV_KMADA32 (long t, unsigned long a, unsigned long b)

__STATIC_FORCEINLINE long __RV_KMAXDA32 (long t, unsigned long a, unsigned long b)

__STATIC_FORCEINLINE long __RV_KMDA32 (unsigned long a, unsigned long b)

__STATIC_FORCEINLINE long __RV_KMXDA32 (unsigned long a, unsigned long b)

__STATIC_FORCEINLINE long __RV_KMADS32 (long t, unsigned long a, unsigned long b)

__STATIC_FORCEINLINE long __RV_KMADRS32 (long t, unsigned long a, unsigned long b)

__STATIC_FORCEINLINE long __RV_KMAXDS32 (long t, unsigned long a, unsigned long b)

__STATIC_FORCEINLINE long __RV_KMSDA32 (long t, unsigned long a, unsigned long b)

__STATIC_FORCEINLINE long __RV_KMSXDA32 (long t, unsigned long a, unsigned long b)

__STATIC_FORCEINLINE long __RV_SMDS32 (unsigned long a, unsigned long b)

__STATIC_FORCEINLINE long __RV_SMDRS32 (unsigned long a, unsigned long b)

__STATIC_FORCEINLINE long __RV_SMXDS32 (unsigned long a, unsigned long b)

group NMSIS_Core_DSP_Intrinsic_RV64_32B_PARALLEL_MAC

(RV64 Only) 32-bit Parallel Multiply & Add Instructions

there are 12 (RV64 Only) 32-bit Parallel Multiply & Add Instructions

Functions

__STATIC_FORCEINLINE long __RV_KMADA32 (long t, unsigned long a, unsigned long b)

KMADA32 (Saturating Signed Multiply Two Words and Two Adds)

Type: DSP (RV64 Only)

Syntax:

KMADA32 Rd, Rs1, Rs2
KMAXDA32 Rd, Rs1, Rs2

Purpose

:

Do two signed 32-bit multiplications from 32-bit data in two registers; and then adds the two 64-bit results and 64-bit data in a third register together. The addition result may be saturated.

KMADA32: rd + top*top + bottom*bottom
KMAXDA32: rd + top*bottom + bottom*top

Description

:

For the

KMADA32 instruction, it multiplies the bottom 32-bit element in Rs1 with the bottom 32- bit element in Rs2 and then adds the result to the result of multiplying the top 32-bit element in Rs1 with the top 32-bit element in Rs2. It is actually an alias of the KMAR64 instruction. For the KMAXDA32 instruction, it multiplies the top 32-bit element in Rs1 with the bottom 32-bit element in Rs2 and then adds the result to the result of multiplying the bottom 32-bit element in Rs1 with the top 32-bit element in Rs2. The result is added to the content of 64-bit data in Rd. If the addition result is beyond the Q63 number range (-2^63 <= Q63 <= 2^63-1), it is saturated to the range and the OV bit is set to 1. The 64-bit result is written to Rd. The 32-bit contents of Rs1 and Rs2 are treated as signed integers.

Operations:

res = Rd + (Rs1.W[1] * Rs2.w[1]) + (Rs1.W[0] * Rs2.W[0]); // KMADA32
res = Rd + (Rs1.W[1] * Rs2.W[0]) + (Rs1.W[0] * Rs2.W[1]); // KMAXDA32
if (res > (2^63)-1) {
  res = (2^63)-1;
  OV = 1;
} else if (res < -2^63) {
  res = -2^63;
  OV = 1;
}
Rd = res;

Parameters

t – [in] long type of value stored in t
a – [in] unsigned long type of value stored in a
b – [in] unsigned long type of value stored in b

Returns

value stored in long type

__STATIC_FORCEINLINE long __RV_KMAXDA32 (long t, unsigned long a, unsigned long b)

KMAXDA32 (Saturating Signed Crossed Multiply Two Words and Two Adds)

Type: DSP (RV64 Only)

Syntax:

KMADA32 Rd, Rs1, Rs2
KMAXDA32 Rd, Rs1, Rs2

Purpose

:

Do two signed 32-bit multiplications from 32-bit data in two registers; and then adds the two 64-bit results and 64-bit data in a third register together. The addition result may be saturated.

KMADA32: rd + top*top + bottom*bottom
KMAXDA32: rd + top*bottom + bottom*top

Description

:

For the

KMADA32 instruction, it multiplies the bottom 32-bit element in Rs1 with the bottom 32- bit element in Rs2 and then adds the result to the result of multiplying the top 32-bit element in Rs1 with the top 32-bit element in Rs2. It is actually an alias of the KMAR64 instruction. For the KMAXDA32 instruction, it multiplies the top 32-bit element in Rs1 with the bottom 32-bit element in Rs2 and then adds the result to the result of multiplying the bottom 32-bit element in Rs1 with the top 32-bit element in Rs2. The result is added to the content of 64-bit data in Rd. If the addition result is beyond the Q63 number range (-2^63 <= Q63 <= 2^63-1), it is saturated to the range and the OV bit is set to 1. The 64-bit result is written to Rd. The 32-bit contents of Rs1 and Rs2 are treated as signed integers.

Operations:

res = Rd + (Rs1.W[1] * Rs2.w[1]) + (Rs1.W[0] * Rs2.W[0]); // KMADA32
res = Rd + (Rs1.W[1] * Rs2.W[0]) + (Rs1.W[0] * Rs2.W[1]); // KMAXDA32
if (res > (2^63)-1) {
  res = (2^63)-1;
  OV = 1;
} else if (res < -2^63) {
  res = -2^63;
  OV = 1;
}
Rd = res;

Parameters

t – [in] long type of value stored in t
a – [in] unsigned long type of value stored in a
b – [in] unsigned long type of value stored in b

Returns

value stored in long type

__STATIC_FORCEINLINE long __RV_KMDA32 (unsigned long a, unsigned long b)

KMDA32 (Signed Multiply Two Words and Add)

Type: DSP (RV64 Only)

Syntax:

KMDA32 Rd, Rs1, Rs2
KMXDA32 Rd, Rs1, Rs2

Purpose

:

Do two signed 32-bit multiplications from the 32-bit element of two registers; and then adds the two 64-bit results together. The addition result may be saturated.

KMDA32: top*top + bottom*bottom
KMXDA32: top*bottom + bottom*top

Description

:

For the

KMDA32 instruction, it multiplies the bottom 32-bit element of Rs1 with the bottom 32-bit element of Rs2 and then adds the result to the result of multiplying the top 32-bit element of Rs1 with the top 32-bit element of Rs2. For the KMXDA32 instruction, it multiplies the bottom 32-bit element of Rs1 with the top 32-bit element of Rs2 and then adds the result to the result of multiplying the top 32-bit element of Rs1 with the bottom 32-bit element of Rs2. The addition result is checked for saturation. If saturation happens, the result is saturated to 2^63-1. The final result is written to Rd. The 32-bit contents are treated as signed integers.

Operations:

if ((Rs1 != 0x8000000080000000) or (Rs2 != 0x8000000080000000)) {
  Rd = (Rs1.W[1] * Rs2.W[1]) + (Rs1.W[0] * Rs2.W[0]); // KMDA32
  Rd = (Rs1.W[1] * Rs2.W[0]) + (Rs1.W[0] * Rs2.W[1]); // KMXDA32
} else {
  Rd = 0x7fffffffffffffff;
  OV = 1;
}

Parameters

a – [in] unsigned long type of value stored in a
b – [in] unsigned long type of value stored in b

Returns

value stored in long type

__STATIC_FORCEINLINE long __RV_KMXDA32 (unsigned long a, unsigned long b)

KMXDA32 (Signed Crossed Multiply Two Words and Add)

Type: DSP (RV64 Only)

Syntax:

KMDA32 Rd, Rs1, Rs2
KMXDA32 Rd, Rs1, Rs2

Purpose

:

Do two signed 32-bit multiplications from the 32-bit element of two registers; and then adds the two 64-bit results together. The addition result may be saturated.

KMDA32: top*top + bottom*bottom
KMXDA32: top*bottom + bottom*top

Description

:

For the

KMDA32 instruction, it multiplies the bottom 32-bit element of Rs1 with the bottom 32-bit element of Rs2 and then adds the result to the result of multiplying the top 32-bit element of Rs1 with the top 32-bit element of Rs2. For the KMXDA32 instruction, it multiplies the bottom 32-bit element of Rs1 with the top 32-bit element of Rs2 and then adds the result to the result of multiplying the top 32-bit element of Rs1 with the bottom 32-bit element of Rs2. The addition result is checked for saturation. If saturation happens, the result is saturated to 2^63-1. The final result is written to Rd. The 32-bit contents are treated as signed integers.

Operations:

if ((Rs1 != 0x8000000080000000) or (Rs2 != 0x8000000080000000)) {
  Rd = (Rs1.W[1] * Rs2.W[1]) + (Rs1.W[0] * Rs2.W[0]); // KMDA32
  Rd = (Rs1.W[1] * Rs2.W[0]) + (Rs1.W[0] * Rs2.W[1]); // KMXDA32
} else {
  Rd = 0x7fffffffffffffff;
  OV = 1;
}

Parameters

a – [in] unsigned long type of value stored in a
b – [in] unsigned long type of value stored in b

Returns

value stored in long type

__STATIC_FORCEINLINE long __RV_KMADS32 (long t, unsigned long a, unsigned long b)

KMADS32 (Saturating Signed Multiply Two Words & Subtract & Add)

Type: DSP (RV64 Only)

Syntax:

KMADS32 Rd, Rs1, Rs2
KMADRS32 Rd, Rs1, Rs2
KMAXDS32 Rd, Rs1, Rs2

Purpose

:

Do two signed 32-bit multiplications from 32-bit elements in two registers; and then perform a subtraction operation between the two 64-bit results. Then add the subtraction result to 64-bit data in a third register. The addition result may be saturated.

KMADS32: rd + (top*top - bottom*bottom)
KMADRS32: rd + (bottom*bottom - top*top)
KMAXDS32: rd + (top*bottom - bottom*top)

Description

:

For the

KMADS32 instruction, it multiplies the bottom 32-bit element in Rs1 with the bottom 32-bit element in Rs2 and then subtracts the result from the result of multiplying the top 32-bit element in Rs1 with the top 32-bit element in Rs2. For the KMADRS32 instruction, it multiplies the top 32-bit element in Rs1 with the top 32-bit element in Rs2 and then subtracts the result from the result of multiplying the bottom 32-bit element in Rs1 with the bottom 32-bit element in Rs2. For the KMAXDS32 instruction, it multiplies the bottom 32-bit element in Rs1 with the top 32-bit element in Rs2 and then subtracts the result from the result of multiplying the top 32-bit element in Rs1 with the bottom 32-bit element in Rs2. The subtraction result is then added to the content of 64-bit data in Rd. If the addition result is beyond the Q63 number range (-2^63 <= Q63 <= 2^63-1), it is saturated to the range and the OV bit is set to

The 64-bit result after saturation is written to Rd. The 32-bit contents of Rs1 and Rs2 are treated as signed integers.

Operations:

res = Rd + (Rs1.W[1] * Rs2.W[1]) - (Rs1.W[0] * Rs2.W[0]); // KMADS32
res = Rd + (Rs1.W[0] * Rs2.W[0]) - (Rs1.W[1] * Rs2.W[1]); // KMADRS32
res = Rd + (Rs1.W[1] * Rs2.W[0]) - (Rs1.W[0] * Rs2.W[1]); // KMAXDS32
if (res > (2^63)-1) {
  res = (2^63)-1;
  OV = 1;
} else if (res < -2^63) {
  res = -2^63;
  OV = 1;
}
Rd = res;

Parameters

t – [in] long type of value stored in t
a – [in] unsigned long type of value stored in a
b – [in] unsigned long type of value stored in b

Returns

value stored in long type

__STATIC_FORCEINLINE long __RV_KMADRS32 (long t, unsigned long a, unsigned long b)

KMADRS32 (Saturating Signed Multiply Two Words & Reverse Subtract & Add)

Type: DSP (RV64 Only)

Syntax:

KMADS32 Rd, Rs1, Rs2
KMADRS32 Rd, Rs1, Rs2
KMAXDS32 Rd, Rs1, Rs2

Purpose

:

Do two signed 32-bit multiplications from 32-bit elements in two registers; and then perform a subtraction operation between the two 64-bit results. Then add the subtraction result to 64-bit data in a third register. The addition result may be saturated.

KMADS32: rd + (top*top - bottom*bottom)
KMADRS32: rd + (bottom*bottom - top*top)
KMAXDS32: rd + (top*bottom - bottom*top)

Description

:

For the

KMADS32 instruction, it multiplies the bottom 32-bit element in Rs1 with the bottom 32-bit element in Rs2 and then subtracts the result from the result of multiplying the top 32-bit element in Rs1 with the top 32-bit element in Rs2. For the KMADRS32 instruction, it multiplies the top 32-bit element in Rs1 with the top 32-bit element in Rs2 and then subtracts the result from the result of multiplying the bottom 32-bit element in Rs1 with the bottom 32-bit element in Rs2. For the KMAXDS32 instruction, it multiplies the bottom 32-bit element in Rs1 with the top 32-bit element in Rs2 and then subtracts the result from the result of multiplying the top 32-bit element in Rs1 with the bottom 32-bit element in Rs2. The subtraction result is then added to the content of 64-bit data in Rd. If the addition result is beyond the Q63 number range (-2^63 <= Q63 <= 2^63-1), it is saturated to the range and the OV bit is set to

The 64-bit result after saturation is written to Rd. The 32-bit contents of Rs1 and Rs2 are treated as signed integers.

Operations:

res = Rd + (Rs1.W[1] * Rs2.W[1]) - (Rs1.W[0] * Rs2.W[0]); // KMADS32
res = Rd + (Rs1.W[0] * Rs2.W[0]) - (Rs1.W[1] * Rs2.W[1]); // KMADRS32
res = Rd + (Rs1.W[1] * Rs2.W[0]) - (Rs1.W[0] * Rs2.W[1]); // KMAXDS32
if (res > (2^63)-1) {
  res = (2^63)-1;
  OV = 1;
} else if (res < -2^63) {
  res = -2^63;
  OV = 1;
}
Rd = res;

Parameters

t – [in] long type of value stored in t
a – [in] unsigned long type of value stored in a
b – [in] unsigned long type of value stored in b

Returns

value stored in long type

__STATIC_FORCEINLINE long __RV_KMAXDS32 (long t, unsigned long a, unsigned long b)

KMAXDS32 (Saturating Signed Crossed Multiply Two Words & Subtract & Add)

Type: DSP (RV64 Only)

Syntax:

KMADS32 Rd, Rs1, Rs2
KMADRS32 Rd, Rs1, Rs2
KMAXDS32 Rd, Rs1, Rs2

Purpose

:

Do two signed 32-bit multiplications from 32-bit elements in two registers; and then perform a subtraction operation between the two 64-bit results. Then add the subtraction result to 64-bit data in a third register. The addition result may be saturated.

KMADS32: rd + (top*top - bottom*bottom)
KMADRS32: rd + (bottom*bottom - top*top)
KMAXDS32: rd + (top*bottom - bottom*top)

Description

:

For the

KMADS32 instruction, it multiplies the bottom 32-bit element in Rs1 with the bottom 32-bit element in Rs2 and then subtracts the result from the result of multiplying the top 32-bit element in Rs1 with the top 32-bit element in Rs2. For the KMADRS32 instruction, it multiplies the top 32-bit element in Rs1 with the top 32-bit element in Rs2 and then subtracts the result from the result of multiplying the bottom 32-bit element in Rs1 with the bottom 32-bit element in Rs2. For the KMAXDS32 instruction, it multiplies the bottom 32-bit element in Rs1 with the top 32-bit element in Rs2 and then subtracts the result from the result of multiplying the top 32-bit element in Rs1 with the bottom 32-bit element in Rs2. The subtraction result is then added to the content of 64-bit data in Rd. If the addition result is beyond the Q63 number range (-2^63 <= Q63 <= 2^63-1), it is saturated to the range and the OV bit is set to

The 64-bit result after saturation is written to Rd. The 32-bit contents of Rs1 and Rs2 are treated as signed integers.

Operations:

res = Rd + (Rs1.W[1] * Rs2.W[1]) - (Rs1.W[0] * Rs2.W[0]); // KMADS32
res = Rd + (Rs1.W[0] * Rs2.W[0]) - (Rs1.W[1] * Rs2.W[1]); // KMADRS32
res = Rd + (Rs1.W[1] * Rs2.W[0]) - (Rs1.W[0] * Rs2.W[1]); // KMAXDS32
if (res > (2^63)-1) {
  res = (2^63)-1;
  OV = 1;
} else if (res < -2^63) {
  res = -2^63;
  OV = 1;
}
Rd = res;

Parameters

t – [in] long type of value stored in t
a – [in] unsigned long type of value stored in a
b – [in] unsigned long type of value stored in b

Returns

value stored in long type

__STATIC_FORCEINLINE long __RV_KMSDA32 (long t, unsigned long a, unsigned long b)

KMSDA32 (Saturating Signed Multiply Two Words & Add & Subtract)

Type: DSP (RV64 Only)

Syntax:

KMSDA32 Rd, Rs1, Rs2
KMSXDA32 Rd, Rs1, Rs2

Purpose

:

Do two signed 32-bit multiplications from the 32-bit element of two registers; and then subtracts the two 64-bit results from a third register. The subtraction result may be saturated.

KMSDA: rd - top*top - bottom*bottom
KMSXDA: rd - top*bottom - bottom*top

Description

:

For the

KMSDA32 instruction, it multiplies the bottom 32-bit element of Rs1 with the bottom 32-bit element of Rs2 and multiplies the top 32-bit element of Rs1 with the top 32-bit element of Rs2. For the KMSXDA32 instruction, it multiplies the bottom 32-bit element of Rs1 with the top 32-bit element of Rs2 and multiplies the top 32-bit element of Rs1 with the bottom 32-bit element of Rs2. The two 64-bit multiplication results are then subtracted from the content of Rd. If the subtraction result is beyond the Q63 number range (-2^63 <= Q63 <= 2^63-1), it is saturated to the range and the OV bit is set to 1. The result after saturation is written to Rd. The 32-bit contents are treated as signed integers.

Operations:

res = Rd - (Rs1.W[1] * Rs2.W[1]) - (Rs1.W[0] * Rs2.W[0]); // KMSDA32
res = Rd - (Rs1.W[1] * Rs2.W[0]) - (Rs1.W[0] * Rs2.W[1]); // KMSXDA32
if (res > (2^63)-1) {
  res = (2^63)-1;
  OV = 1;
} else if (res < -2^63) {
  res = -2^63;
  OV = 1;
}
Rd = res;

Parameters

t – [in] long type of value stored in t
a – [in] unsigned long type of value stored in a
b – [in] unsigned long type of value stored in b

Returns

value stored in long type

__STATIC_FORCEINLINE long __RV_KMSXDA32 (long t, unsigned long a, unsigned long b)

KMSXDA32 (Saturating Signed Crossed Multiply Two Words & Add & Subtract)

Type: DSP (RV64 Only)

Syntax:

KMSDA32 Rd, Rs1, Rs2
KMSXDA32 Rd, Rs1, Rs2

Purpose

:

Do two signed 32-bit multiplications from the 32-bit element of two registers; and then subtracts the two 64-bit results from a third register. The subtraction result may be saturated.

KMSDA: rd - top*top - bottom*bottom
KMSXDA: rd - top*bottom - bottom*top

Description

:

For the

KMSDA32 instruction, it multiplies the bottom 32-bit element of Rs1 with the bottom 32-bit element of Rs2 and multiplies the top 32-bit element of Rs1 with the top 32-bit element of Rs2. For the KMSXDA32 instruction, it multiplies the bottom 32-bit element of Rs1 with the top 32-bit element of Rs2 and multiplies the top 32-bit element of Rs1 with the bottom 32-bit element of Rs2. The two 64-bit multiplication results are then subtracted from the content of Rd. If the subtraction result is beyond the Q63 number range (-2^63 <= Q63 <= 2^63-1), it is saturated to the range and the OV bit is set to 1. The result after saturation is written to Rd. The 32-bit contents are treated as signed integers.

Operations:

res = Rd - (Rs1.W[1] * Rs2.W[1]) - (Rs1.W[0] * Rs2.W[0]); // KMSDA32
res = Rd - (Rs1.W[1] * Rs2.W[0]) - (Rs1.W[0] * Rs2.W[1]); // KMSXDA32
if (res > (2^63)-1) {
  res = (2^63)-1;
  OV = 1;
} else if (res < -2^63) {
  res = -2^63;
  OV = 1;
}
Rd = res;

Parameters

t – [in] long type of value stored in t
a – [in] unsigned long type of value stored in a
b – [in] unsigned long type of value stored in b

Returns

value stored in long type

__STATIC_FORCEINLINE long __RV_SMDS32 (unsigned long a, unsigned long b)

SMDS32 (Signed Multiply Two Words and Subtract)

Type: DSP (RV64 Only)

Syntax:

SMDS32 Rd, Rs1, Rs2
SMDRS32 Rd, Rs1, Rs2
SMXDS32 Rd, Rs1, Rs2

Purpose

:

Do two signed 32-bit multiplications from the l 32-bit element of two registers; and then perform a subtraction operation between the two 64-bit results.

SMDS32: top*top - bottom*bottom
SMDRS32: bottom*bottom - top*top
SMXDS32: top*bottom - bottom*top

Description

:

For the

SMDS32 instruction, it multiplies the bottom 32-bit element of Rs1 with the bottom 32-bit element of Rs2 and then subtracts the result from the result of multiplying the top 32-bit element of Rs1 with the top 32-bit element of Rs2. For the SMDRS32 instruction, it multiplies the top 32-bit element of Rs1 with the top 32-bit element of Rs2 and then subtracts the result from the result of multiplying the bottom 32-bit element of Rs1 with the bottom 32-bit element of Rs2. For the SMXDS32 instruction, it multiplies the bottom 32-bit element of Rs1 with the top 32-bit element of Rs2 and then subtracts the result from the result of multiplying the top 32-bit element of Rs1 with the bottom 32-bit element of Rs2. The subtraction result is written to Rd. The 32-bit contents of Rs1 and Rs2 are treated as signed integers.

Operations:

Rt = (Rs1.W[1] * Rs2.W[1]) - (Rs1.W[0] * Rs2.W[0]); // SMDS32
Rt = (Rs1.W[0] * Rs2.W[0]) - (Rs1.W[1] * Rs2.W[1]); // SMDRS32
Rt = (Rs1.W[1] * Rs2.W[0]) - (Rs1.W[0] * Rs2.W[1]); // SMXDS32

Parameters

a – [in] unsigned long type of value stored in a
b – [in] unsigned long type of value stored in b

Returns

value stored in long type

__STATIC_FORCEINLINE long __RV_SMDRS32 (unsigned long a, unsigned long b)

SMDRS32 (Signed Multiply Two Words and Reverse Subtract)

Type: DSP (RV64 Only)

Syntax:

SMDS32 Rd, Rs1, Rs2
SMDRS32 Rd, Rs1, Rs2
SMXDS32 Rd, Rs1, Rs2

Purpose

:

Do two signed 32-bit multiplications from the l 32-bit element of two registers; and then perform a subtraction operation between the two 64-bit results.

SMDS32: top*top - bottom*bottom
SMDRS32: bottom*bottom - top*top
SMXDS32: top*bottom - bottom*top

Description

:

For the

SMDS32 instruction, it multiplies the bottom 32-bit element of Rs1 with the bottom 32-bit element of Rs2 and then subtracts the result from the result of multiplying the top 32-bit element of Rs1 with the top 32-bit element of Rs2. For the SMDRS32 instruction, it multiplies the top 32-bit element of Rs1 with the top 32-bit element of Rs2 and then subtracts the result from the result of multiplying the bottom 32-bit element of Rs1 with the bottom 32-bit element of Rs2. For the SMXDS32 instruction, it multiplies the bottom 32-bit element of Rs1 with the top 32-bit element of Rs2 and then subtracts the result from the result of multiplying the top 32-bit element of Rs1 with the bottom 32-bit element of Rs2. The subtraction result is written to Rd. The 32-bit contents of Rs1 and Rs2 are treated as signed integers.

Operations:

Rt = (Rs1.W[1] * Rs2.W[1]) - (Rs1.W[0] * Rs2.W[0]); // SMDS32
Rt = (Rs1.W[0] * Rs2.W[0]) - (Rs1.W[1] * Rs2.W[1]); // SMDRS32
Rt = (Rs1.W[1] * Rs2.W[0]) - (Rs1.W[0] * Rs2.W[1]); // SMXDS32

Parameters

a – [in] unsigned long type of value stored in a
b – [in] unsigned long type of value stored in b

Returns

value stored in long type

__STATIC_FORCEINLINE long __RV_SMXDS32 (unsigned long a, unsigned long b)

SMXDS32 (Signed Crossed Multiply Two Words and Subtract)

Type: DSP (RV64 Only)

Syntax:

SMDS32 Rd, Rs1, Rs2
SMDRS32 Rd, Rs1, Rs2
SMXDS32 Rd, Rs1, Rs2

Purpose

:

Do two signed 32-bit multiplications from the l 32-bit element of two registers; and then perform a subtraction operation between the two 64-bit results.

SMDS32: top*top - bottom*bottom
SMDRS32: bottom*bottom - top*top
SMXDS32: top*bottom - bottom*top

Description

:

For the

SMDS32 instruction, it multiplies the bottom 32-bit element of Rs1 with the bottom 32-bit element of Rs2 and then subtracts the result from the result of multiplying the top 32-bit element of Rs1 with the top 32-bit element of Rs2. For the SMDRS32 instruction, it multiplies the top 32-bit element of Rs1 with the top 32-bit element of Rs2 and then subtracts the result from the result of multiplying the bottom 32-bit element of Rs1 with the bottom 32-bit element of Rs2. For the SMXDS32 instruction, it multiplies the bottom 32-bit element of Rs1 with the top 32-bit element of Rs2 and then subtracts the result from the result of multiplying the top 32-bit element of Rs1 with the bottom 32-bit element of Rs2. The subtraction result is written to Rd. The 32-bit contents of Rs1 and Rs2 are treated as signed integers.

Operations:

Rt = (Rs1.W[1] * Rs2.W[1]) - (Rs1.W[0] * Rs2.W[0]); // SMDS32
Rt = (Rs1.W[0] * Rs2.W[0]) - (Rs1.W[1] * Rs2.W[1]); // SMDRS32
Rt = (Rs1.W[1] * Rs2.W[0]) - (Rs1.W[0] * Rs2.W[1]); // SMXDS32

Parameters

a – [in] unsigned long type of value stored in a
b – [in] unsigned long type of value stored in b

Returns

value stored in long type