It looks like nobody actually answered the question about what the bold stuff means. Here we go...
Each Command sequence comprises of one or more 16-bit instructions. Some instructions are followed by an operand, which is usually an address.
Each 16-bit instruction is coded as follows:
msb|15 10|9 8|7 0|lsb
|. . . . . .|. .|. . . . . . . .|
| OpCode | P | Cmd |
Where Opcode (6-bits [15:10]) is typically:
OPCODE_STOP = 0, //Stop execution and deassert CS
OPCODE_CMD = 1, //Execute command specified in the operand
OPCODE_ADDR = 2, //Provide address cycles for 'operand' number of bits
OPCODE_DUMMY = 3, //Provide the number of dummy cycles in the operand
OPCODE_MODE = 4, //Send flash-specific mode specified in 8-bit operand
OPCODE_MODE2 = 5, //Send flash-specific mode specified in 2-bit operand
OPCODE_MODE4 = 6, //Send flash-specific mode specified in 4-bit operand
OPCODE_READ = 7, //Receive from flash device the number of bytes in the operand
OPCODE_WRITE = 8, //Send to flash device the number of bytes in the operand
OPCODE_JMP_ON_CS = 9, //Jump to instruction index in the operand, if CS is deasserted
OPCODE_ADDR_DDR = 10, //Same as OPCODE_ADDR, but transmit at each clock edge
OPCODE_MODE_DDR = 11, //Same as OPCODE_MODE, but transmit at each clock edge
OPCODE_MODE2_DDR = 12, //Same as OPCODE_MODE2, but transmit at each clock edge
OPCODE_MODE4_DDR = 13, //Same as OPCODE_MODE4, but transmit at each clock edge
OPCODE_READ_DDR = 14, //Same as OPCODE_READ, but transmit at each clock edge
OPCODE_WRITE_DDR = 15, //Same as OPCODE_WRITE, but transmit at each clock edge
OPCODE_DATA_LEARN = 16, //Learn correct DDR sampling point using the given number of data bytes
OPCODE_CMD_DDR = 17, //Same as OPCODE_CMD, but transmit at each clock edge
OPCODE_CADDR = 18, //Provide column address cycles for 'operand' number of bits
OPCODE_CADDR_DDR = 19, //Same as OPCODE_CADDR, but transmit at each clock edge
Where P (2 bits [9:8]) is the number of data pins for data transfer. Values:
DATAPINS_1 = 0, // Use 1 pin
DATAPINS_2 = 1, // Use 2 pins,
DATAPINS_4 = 2, // Use 4 pins
DATAPINS_8 = 3, // Use 8 pins,
Where Cmd - 8 bits [7:0] - NOR Flash Command as per the product Datasheet.